Oral History Transcript — Dr. Frederick Hunt
This transcript may not be quoted, reproduced or redistributed in whole or in part by any means except with the written permission of the American Institute of Physics.
This transcript is based on a tape-recorded interview deposited at the Center for History of Physics of the American Institute of Physics. The AIP's interviews have generally been transcribed from tape, edited by the interviewer for clarity, and then further edited by the interviewee. If this interview is important to you, you should consult earlier versions of the transcript or listen to the original tape. For many interviews, the AIP retains substantial files with further information about the interviewee and the interview itself. Please contact us for information about accessing these materials.
Please bear in mind that: 1) This material is a transcript of the spoken word rather than a literary product; 2) An interview must be read with the awareness that different people's memories about an event will often differ, and that memories can change with time for many reasons including subsequent experiences, interactions with others, and one's feelings about an event. Disclaimer: This transcript was scanned from a typescript, introducing occasional spelling errors. The original typescript is available.
See the catalog record for this interview and search for other interviews in our collection
Interview with Dr. Frederick Hunt
Frederick Hunt; January 8, 1965
ABSTRACT: Covers Hunt’s life and career to 1965. Childhood and high school years, l905-1920; undergraduate life and education at Ohio State University, l920-l925 graduate work at Harvard, l925-1932: realization of his place in physics, research and problems with doctoral thesis; research on architectural acoustics and reflections on his teaching post at Harvard, 1932—1945: cascade and frequency meter, relations in department, conflicts between teaching and research function, development of slight weight pickup and side wall support war work on Navy acoustic mine sweeping project, NERC underwater sound project— recruitment, management problems, and dismantlement instigating Navy postwar research and problems in underwater sound: creation and problems of the Engineering Science and Applied Physics department at Harvard, 1946—1965: reflections on development of the Acoustical Society of America since l930s assessment of his contributions; place of acoustics as a field of study.
Session I | Session II
Weiner:The interview has resumed. It is January 8, 1965 in the Faculty Room in the Lyman Laboratory of Physics with the same personnel as last time and we are now continuing the interview.
Beranek:This is Leo Beranek again, and we are back at the table in the Faculty Room. We finished last time the section of Professor Hunt’s life that got him his earned doctorate and he also mentioned that later he received an honorary degree. We will want to go into that more when the appropriate point comes in our interview today. Ted, you said you had a few corrections. Maybe we ought to put those in before we go ahead.
Hunt:In retrospect, I discovered when I was looking up the dates, I saw that I had killed my father off a year too early. Dad died on the 8th of December 1955 (I think I said 1954). He had been in the bank in Barnesville, Ohio, 66 years and 3 months, and had been President of the bank the last 16 years of his career which was almost the last 16 years of his life. The second correction is really an amendment. You had asked me about whether I was an outdoors boy or whether I spent my time indoors reading. I think I claimed to be an outdoors boy, but in retrospect, I think one characteristic that impresses me now as being different from that of some of my friends was what I would call a capacity for aloneness. This is not a liking for solitude as such, but more a lack of the need for having people around all the time. This perhaps is the reason why it was congenial for me to make the trip West in the summer of 1925 all alone. Fortunately, my wife shares some of this. We aren’t what you would call anti-social but neither do we feel any particular urge to go out all the time or have people in all the time. I find sometimes this is a difference—the ability to be perfectly comfortable living with yourself. The third correction—you remarked about my uniform habits of dress—and I had a feeling that in self defense I had to put into evidence the fact that my son went to college on the West Coast and turned into a native Californian and that by 1957 he had converted me to the sport shirt cult, the sport jacket cult, and a few years later into the sport car cult. So that In self defense against this allegation of uniformity I had to appear today in a sport shirt.
Beranek:I might say that Ted’s sport shirt is a maroon shirt with a black tie which completely upsets my statement of last time.
Weiner:As long as it doesn’t upset your esthetic sensibilities.
Beranek:I had the idea before we came here that perhaps we could speak of your life since your doctorate in three time periods: the era of your personal research which extended up until World War II with relatively few doctoral students; and then the period of public service which started with the beginning of World War II and ran on through quite a period afterwards...
Hunt:Practically until now.
Beranek:And then a period of getting others to be research contributors through the process of creating doctorates, in fact, many doctoral candidates have come through your hands. I have a list that you handed me of the subjects in which you have done research or have encouraged others to do research, and I would suggest that we proceed by some mixture of these two ways of cutting things. Why don’t you start off with the period after you got your doctorate and take up these two principal areas, perhaps the beginning of architectural acoustics and instrumentation and electronic circuitry?
I thought I might start that by adding another footnote which corroborates the answers I gave before to your question of how I got started in acoustics. I think I mentioned that it was largely opportunistic. It was also perhaps opportunistic in the sense of assisting Professor Pierce’s course by running the laboratory work and becoming aware in the course of trying to do laboratory experiments that there was a lot of subject matter that I was learning that was not being taught in the course. There didn’t seem to be any room to put it in the course and by 1933 or 1934 it became clear to me that there was an opportunity to teach the material that I could teach in the curriculum as a supplement to what was already being done. Now, of course, this feeds upon itself and so this provides the motivation for undertaking some of the research to do some of these things better. I think this was the way we got into the problems of measuring reverberation time because we tried to do laboratory experiments on measuring it and it wasn’t easy, so you go to work on the instrumentation for improving it. And this was what sparked the interest in working on level recorders.
Then the relay system we had for making precision measurements—you may remember the experiment when we could detect the presence of one square foot of celotex sitting lonesomely in the center of the floor of the Sabine reverberation chamber. This you couldn’t do by conventional techniques but with our so-called precision method, one could do this. Of course, this was about the time that the first edition of Morse’s book appeared in 1934. I had been recently married and was living on the second floor of a house on Kirkland Street. The downstairs neighbor was an MIT professor Wilmer L. Barrow, and a backyard neighbor was Professor Morse. He saw Barrow frequently and I saw Barrow frequently and working partly through Barrow as a relay point, I would tell Barrow what ought to be put into a textbook, the problems we didn’t know how to solve, and he would hand these problems to Morse. In this indirect way I think I may have been responsible for stimulating Morse to work up the normal mode attack on room acoustics. Of course, for him this was also merely a conversion of his work on atomic spectra, but the fact that this was a needed thing in the field of architectural acoustics—Morse never gave me credit for having anything to do with instigating that, but at least I was in there somewhere. When this came out, this immediately launched us, this broke the ice on the normal mode attack on the room acoustics problem. You will also recall that we were very annoyed at some of the approximations Morse had made. Morse threw away factors which we thought were as important as some of the ones he kept. And so we were trying to improve the precision and in particular we were trying to do some things experimentally that had been merely paper exercises as far as he was concerned.
Weiner:Would you give us the full title of Morse’s book?
Hunt:Vibration and Sound, which was one of McGraw-Hills International Series in Science.
Weiner:Who was the “we” you refer to very often?
Hunt:Dr. Beranek and I. In this respect, part of the “we” was Wilmer Barrow, who was my neighbor.
Beranek:I think I mentioned in the last interview that I arrived at Harvard in the fall of 1936 and then by 1937 I was joined together with Ted a little bit part-time, and then by 1938 I was his full-time assistant.
Hunt:So that it was Beranek and Hunt and Dah You Maa and R. B. Watson and R. H. Wallace and W. Rudmose.
Beranek:Could you give us some feeling for this method of measuring reverberation which you gave a paper on in the spring of 1936 and then published in 1936. That preceded my arrival.
Hunt:It was a simple scheme for letting the room decay to a lower threshold. This tripped a relay which automatically started the loudspeaker again. As soon as the sound state had built up to the initial level this operated another relay and started the decay cycle. So that you pushed the button and it went through these decay cycles automatically and an electric timer accumulated the time for ten successive decays. It could be read to high precision so you had the tenfold accuracy and got out a nice single number for the intensity interval spanned by the setting on an attenuator. You could change that and pick off successive points on a decay curve to much better precision than had been available before.
Beranek:There was a little by-light on this that we ought to cover and that is the room in which you made your measurements and what historically had happened in there.
Hunt:My thesis work had been done in the northwest basement room in Lyman which was a room fitted with a refrigerator door. This was my reverberation chamber. That room was subsequently taken over and used by Professor Pierce and Dr. Griffin and Dr. Galambos for the first measurements on the echo ranging of bats-this became the bat room. In the meantime, I moved my experiments to the Sabine reverberation chamber, the old constant temperature room in the basement of the Jefferson Laboratory.
Beranek:And that was Wallace Clement Sabine.
Hunt:Yes, this was the constant temperature room in which he had done his pioneer work in 1895 to 1898. In fact we called that reverberation chamber—we said Harvard was the birthplace of acoustics and that was the cradle. Of course, as we tackled this normal mode approach to the problem, we didn’t like the vaulted ceiling in that room. One of the first things we did was to make the first and only modification that has been made in that room since Wallace Sabine used it and that was to erect a cast concrete roof slab, lowering the ceiling and converting the room into one of the few rectangular parallelepipeds without interior obstructions that know to exist. This sounds like such a simple shape that you’d think you could find these anywhere all over the university but if you look, there aren’t any. There are always doors, interior beams, windows, or something that spoils the geometry of a simple parallelepiped. We wanted this for our theory and we got it by putting a concrete ceiling into the old Sabine chamber. Incidentally, this was a slab with pre-stressed concrete and the Buildings and Grounds Department that installed it had the advice of Dean Westerguard of the Engineering School who was the pre-stress concrete expert.
Beranek:This was a relatively new subject.
Hunt:A new technique at that time.
Beranek:I don’t want to spend too much time on this but I might add another little anecdote. Walking into this region, there was a control room on the ground floor and the ceiling of this control room had racks that held—probably still does— hundreds of organ pipes.
Hunt:Most of those have finally been cleaned out now.
Beranek:And then on the other side of the chamber which was actually below this control room, there was an old gasoline engine, I believe, which used to blow the organ pipes. If it wasn’t gasoline, it had an awful oily smell—maybe it was an electric motor driving a blower.
Hunt:I think the blower and the bellows were in the room above—I guess the fan was outside and the bellows were inside over the chamber and this was the air source for Sabine’s little organ which was his sound source in that room.
Beranek:Because he didn’t have loudspeakers in his day.
Hunt:The rotating vanes and the hole through and the bearing for that we still used and still do use in the same form that Sabine used it.
Weiner:Are there any photographs that you know of that show the room as it existed in this period?
Hunt:In Wallace Clement Sabine’s Collected Papers on Acoustics which is just now out in a Dover reprint.
Weiner:What about the modifications that were made in the thirties? Were there any photographs that will show that?
Hunt:I think not. It’s not a good place with nothing to photograph except a flat ceiling.
Beranek:I have some pictures with an experiment going on in my collection in that room. But in addition to that, there was a funny box that used to sort of fold up and go in a corner of the room.
Hunt:Oh yes, that was Sabine’s Turkish bath box. This was a wooden enclosure in which he could sit with only his head projecting out. It had a little glass window so that the projecting head could look through the glass window to read the stopwatch which he could manipulate from the inside.
Beranek:Where is that box today?
Hunt:I don’t know whether we preserved that or not. There was a clean-up a few years ago. Some of the surplus pipes were thrown out. Samples were kept by David Wheatland in his historical collection, and I suspect that the box might have finally gone the way…
Beranek:Let’s go on now, please.
Hunt:The climax of this work on normal modes was the Hunt, Beranek and Maa paper in 1939, “Analysis of Sound Decay in Rectangular Rooms.” It was the analysis of sound decay and also the analysis of the steady state. We felt that we had in that paper, in effect, cleaned up the rectangular room. And to the best of my knowledge this is still so, and if one wants to study what goes on in a rectangular room I don’t yet know of any better reference than that paper. We took this paper to the Tenth Anniversary meeting of the Acoustical Society of America at New York and presented it with a good bit of satisfaction. One of the great disappointments in my technical life was the fact that Maxfield and his collaborators from ERPI (Electrical Research Products, Inc.) had a paper at the same meeting on a recording studio, which showed unequivocally and beyond challenge the fact that almost the worst thing you could do to make a room satisfactory acoustically would be to make it in the form of a rectangular parallelepiped. So that the conditions which made a room pleasant and good in the sense of the listener meant that you had to depart with systematic statistics from the kind of uniformity and regularity that we knew how to deal with analytically. This meant that our analytical approach was a fine idealization but had little relation to the description of conditions in rooms that are desirable acoustically.
Weiner:Was this recognized by anyone at the meeting?
Hunt:The Bell people who presented this paper were quite sure that you had to do this steadied irregularity, the random distribution of absorbing material, the steadied distribution of diffusing agents.
Weiner:But did they recognize it in reference to your paper, as a criticism perhaps of your approach?
Hunt:I think they weren’t very much interested in our approach. We were the long-haired academics working on a nice problem in physics that didn’t have anything to do with how you make good studios. I think our present position—you know more about this than I do, Leo—would be that one who is going to practice the art of random distribution of diffusing agents needs to understand the behavior of sound in rectangular enclosures in order to provide a sound basis for his deviations from it. So I think our work is not wholly useless, but it was a disappointment not to feel that we could proceed on this line toward the prescription of conditions for good listening, which, of course, had been the goal that Wallace Sabine had always pursued. I suppose in one sense that the fact that we were very soon thereafter diverted by war work kept us from bumping our heads against this rough ceiling. Certainly, in my own case, I think this sense of frustration is one of the reasons why I was reluctant to go back to the field of architectural acoustics after the war. I had the feeling that this might be a good game to get into again if you had a good idea about what to measure. I think we still don’t know exactly what to measure in these rooms although Beranek’s colleagues have really been making a lot of progress on that in the last ten years.
Beranek:Mainly what we’ve shown is that it’s so complicated that there is no simple measure. You have to measure many things and take them into account. Ted, one point on this. This paper which was completed and published is now the end of my first year as a full-time assistant to you. Do you have any comments on having an assistant? This was probably one of the first times you’d really had a full-time assistant and I wondered what your thoughts were on this subject.
Hunt:I think my attitude then was the same as it would be now. I’ve always had more ideas than I had time to carry out with my own hands, and having wise hands to whom you can say: “Why don’t you try this?”—this is wonderful. This is the way to do research. Yes, it was fine having an assistant, and I’ve been pretty fortunate since then, in one way or another, to be surrounded with what you might call fertile ground on which to cast these suggestions of why don’t you try this.
Beranek:Ted, you made us all work terribly hard. I never was so tired in my life and in fact I think I worried you at the end of this period by getting overly tired. Do you remember the long nights that were spent on the computations?
Hunt:Oh yes. Of course, this didn’t impress me very much because I could always get along with less sleep than most of my friends. Working so that you only got six hours sleep, that was par. Who wanted to waste their time sleeping any more than that? Yes, I was nominally sympathetic but as long as I wasn’t getting any more sleep than that, why should these other fellows get so much sleep?
Beranek:I was thinking too of the combination of calculating instruments?
Hunt:Yes, you mean the episode on the top floor of Lyman when we were calculating normal frequencies.
Beranek:For this same paper, I think.
Hunt:Yes, and this was a lot of tedious calculation, square roots of sums of squares of three numbers with lots of figures, so we called on assistants. Around the table were Beranek, Bob Wallace and Dah You Maa, and I think with occasional kibitzing by Bob Watson (Robert B. Watson, son of Floyd Watson). And Beranek had a 20-inch slide rule, Bob Wallace had a desk calculator, and Dah You Maa sat there with a neat little abacus. Of course, they were checking each other because you didn’t believe your own calculations in this. And systematically, Maa with his abacus would clean the slide rule and the desk calculator every time. He would sit there with his answer waiting for you fellows to get your answer so that he could compare with you. This was a very comical scene. It produced a lot of good numbers and also a lot of merriment.
Weiner:Was Maa a Ph.D. student?
Hunt:He and Leo were my first two successful Ph.D. candidates. They were two bright boys. I wish they all came like this.
Beranek:We might finish about Maa as you probably won’t interview him directly. He returned to China after getting his Ph.D. the same year I did (in 1940). Of course, the Japanese had been in China up until some time after the war—no, I don’t mean that.
Hunt:They were in the process of invading. Do you remember the letter you had from Maa? He was teaching...
Beranek:Let me get this straight. Japan had been in China at the time Maa was here and his family had retreated west of Peking—his native city was Peking—and they had retreated west. There were all these atrocities against the Chinese by the Japanese. It was a very bad situation and he worried a good deal about this. I was very close to him in this period. Then when he got his doctorate, apparently this Japanese thing had subsided. They had gotten out of there—I don’t remember the dates—and then the threat came from the north of Communist China, of the Communists invading. And Maa wrote me a letter which I still have, in which—but this is later though, the Communists didn’t come until after World War II, did they?
Hunt:No, what I was remembering was the time—he was teaching and the students would go up in the hills with their books when an air raid was coming and they would do their studying sometimes behind rocks and so on.
Beranek:That was the Japanese still?
Hunt:Yes, that was then the Japanese were invading and sweeping over the mainland. Then when the air raid would be over they would go back to the classroom, if there was a classroom to go back to.
Beranek:Then after World War I when the Communists were coming down from the north, he wrote me a letter and invited me to come and spend a year as a professor in the Peking National University. And he had a very cute little phrase in there, “You may be worried about the forward movement of the Communists from the north,” but he says, “You needn’t worry—we have a very large wall around Peking.” I don’t know whether he meant it as a joke but it was put in the letter straight-face. Obviously, I didn’t go, and the Chinese very quickly after that took over. Now Maa became the head of the department of electrical engineering in Peking University under the Communists in Communist China and since then has written quite a number of propaganda papers about the glory of science in a socialist country, and is quite a leading administrator in electrical engineering in the national picture in Communist China.
Weiner:Is he in acoustics today?
Beranek:I think he is an administrator entirely-—that is what his writings are.
Hunt:One of our chickens that got lost.
Beranek:Yes, Ted, is there more in architectural acoustics you would like to talk about?
Hunt:I think that’s about the story on architectural acoustics. In the same period, we mentioned instrumentation and electronic circuitry—I mentioned the frequency meter, the level recorder. I recall two papers that I wrote with Dr. Hickman (Roger W. Hickman), one on the exact measurement of electron tube coefficients which we thought was a pretty good paper (and it would still be a good paper if you wanted to measure electron tube coefficients any more). This was really a working out in detail the tricks that we had found it useful to employ in conducting laboratory experiments. We had done three or four of the typical cases, then when we came to the paper, we systematized it and did the whole family.
Beranek:How did this interrelate with Chaffee’s big machine for doing this on power tubes?
Hunt:This was rather independent. This was the period when Chaffee was finishing his book on small signal theory and we were still, in effect, doing laboratory work and cleaning this up and he was going on to do the large signal cases. I guess again this was by the stimulation of taking Roger in as a partner—we did a paper on electronic stabilizers, which again I think was a good job. It’s rather interesting, I think, to sometimes go back and review one of these early papers of 20 years ago and see whether it sounds right now. I had to do this because in this paper on electronic stabilizers we invented the cascode and I coined this word—two tubes sitting one on top of the other, one is a plate load for the other. We showed this in a drawing and used it in one of our stabilizers. We didn’t appreciate then the fact that this particular combination had great advantages for signal and noise ratio so that the cascode was picked up during the war and exploited and it is still being used as a good low noise amplifier for radio frequencies. Whereas the configuration is ours, the low noise advantages we were unaware of at the time.
Weiner:I have two questions on that: one, the origin of that term; and secondly, whether a patent is involved in this?
Hunt:The term was a synthetic made out of cascaded triode, one triode on top of the other so that a cascaded triode was called a cascode. We did put it in quotation marks in the paper and this was picked up so that this is another word now in the technical literature. We were a little naive at the time and it didn’t occur to us to patent it. I think it probably was patentable if we had been alert to this possibility, although I don’t know if this would then have covered the low noise advantages that prevail at radio frequency.
Beranek:Speaking of patents, you had one patent that turned out to be quite a factor in your life. Would you like to tell about the development of that?
Hunt:This was the frequency meter and it did play a very interesting role in my life. I developed this circuitry for measuring frequency, meter indication, and this was what you might call functional circuit synthesis. You figure well, if you could make one pulse per cycle and make it in the same size and deliver it to a condenser, all you would have to do would be to measure the voltage on the condenser to get the average number, so you’d juggle and devise the circuitry. At that time I was pretty good at that. So I devised this circuit and in due course published it in the Review of Scientific Instruments. This was a paper, and hurrah, I would go on to something else.
Weiner:Was that published in 1935, “A Direct-Reading Frequency Meter Suitable for High Speed Recording?”
Hunt:That’s right, that’s the one. So about six months after the paper had come out I had a telephone call from Jim Clapp at the General Radio Company saying we’re interested in this circuit, do you have any more details about it, we’d like to build a sample of it, and perhaps we’d like to manufacture it. This was flattering and so I turned my notebooks over to Jim. They built one and it worked for them just as it had for me and this encouraged them so they decided, yes, indeed, they would like to manufacture it. And the General Radio Company, bless their heart, said, “If we manufacture this, we will pay you a royalty for using your circuit, quite independently of whether there is any patent involved or not,” which I think was a fine broad-minded and generous attitude for them to take since it was available in the literature and they could have taken it whether I liked it or not. Then they said, “In addition to that it probably is patentable and if you would like to patent it, we will underwrite the cost of the patent for a half share in it and any royalties we get from licensing somebody else will go first to pay the cost of the patent and then will be divided fifty-fifty.” I had nothing to lose and everything to gain so finally we went ahead and got a patent on it. And this rocked along. They sold a few. I got $50, $75, and then I got a windfall one time, a check for $100 because somebody had found that this frequency meter was the way to translate the information sent back by the weather balloons. So the weather balloon people bought a lot of these frequency meters.
Beranek:How much per unit did you get?
Hunt:5% of the sale price, and I think It was about a $250 instrument.
Beranek:That kind of instrument today would sell for about $600.
Weiner:When was this application to weather balloons? How long after the 1935 publication date?
This must have been about 1939 or 1940. Then when the war came, General Radio built this circuit into a frequency deviation monitor that was sold for monitoring the carrier frequency of broadcast stations. This was the pointer indication of frequency deviation from a crystal. Then General Radio developed a secondary frequency standard with a small crystal in an oven, and again the frequency deviation indicator was this frequency meter circuit—I think it was a type L something—which they built to military specifications for the Navy. Shortly after the outbreak of the war, around 1941 or 1942, the Navy froze the designs. They said we’re not going to tamper with that, we want to buy these, and so this type L secondary frequency standard went into all naval vessels from little sub-chasers up.
Every one of them had one of my frequency meters in it. So all during the war—of course by 1943, the Radiation Laboratory in connection with radar circuits had developed hard tube—this circuit used a couple of little gas thyrotrons—hard tube circuits and limiters had been devised so that the same thing could be done with hard tube circuits over a wider frequency range although with no better accuracy. This design had been frozen, the Navy was happy with it, so all during the war my frequency meter circuit went into these things. Now the thing that made this significant was that—we haven’t come yet to the Harvard Underwater Sound Laboratory, but it was organized on Harvard premises, I was not on leave of absence to serve as its Director but was merely relieved of teaching duties, so that I could serve as its Director.
Throughout the war I continued to be paid at the grade of Associate Professor—I think from one end of the war to the other my salary went up from $5500 to $6500, around the $6000 level. And, of course, expenses went up and the cost of living went up during the war. Throughout this period, the frequency meter just filled in the gap between what Harvard paid me and what I would have received if I’d gone off on leave of absence to MIT to work at the Radiation Laboratory. At the end of the war, bingo, the Navy cancelled all the contracts. General Radio in the meantime was ready to build a hard tube version of the circuit so the royalty check that came at the end of 1945 was the last royalty check and in the spring of 1946 I got my promotion to full professor which just established continuity of my income. So that thanks to the frequency meter, the Hunt family was spared what would have been real financial straits during the war. Then the academic situation picked up the difference so that essentially there had been no discontinuity in income thanks to the frequency meter.
Beranek:Ted, everyone has a feeling of uncertainty in their life about whether they are going to get tenure or not, or maybe even be made an Assistant Professor. I’d like to hear you comment a little bit on your relations with the department, how you viewed your superiors, and did they worry you a little by kind of keeping you on tenterhooks before you got tenure. A few things like that I think would be good for history.
Hunt:I had a feeling that I was always fighting an uphill battle on that score. I think I may have mentioned that I was always just out of phase with the salary changes, also with the promotions. Harvard at that time had the rank of faculty instructor. Annual instructors were appointed for one year. Members of the faculty comprise corporation appointees for more than one year, so that an annual instructor is, by corporation definition, not automatically a member of the faculty. The so-called faculty instructor was, because his appointment was for three years. Of course, this is what I wanted. I think finally got this in 1935. Is that right?
Weiner:From 1931 to 1938 you were Tutor in the Division of Physical Sciences, prior to that you were an Instructor in Physics from 1929-1934. There’s a simultaneous entry there though.
Hunt:Instructor in Physics from 1929-1934—that was an annual instructorship, renewed annually. 1934-1937, Instructor in Physics and Communication Engineering—that was my three-year appointment. So I had one three-year appointment as a faculty instructor which started in 1934.
Beranek:That should read Faculty Instructor really, shouldn’t it?
Hunt:The only way this was recognized was that it was a three-year appointment. It wasn’t in the name.
Beranek:When I was here they made no more assistant professor appointments for a period. They had only faculty instructors.
Hunt:I think I came just a few years later. Then I got an appointment as an assistant professor in 1937 and between 1937 and 1940, before that appointment ran out, was the famous report of the Committee of Eight, and that’s when they abolished the assistant professorship. So I had one which was abolished—I don’t know whether that helped or not, but at least in 1940 I got my appointment as an associate professor. That was a period where there was some turmoil and I had the feeling at least that I was always on the marginal edge.
Beranek:Who was for you and who was against you—to what extent do you want to tell us?
Hunt:I don’t think anybody was against me, I think the situation always is: what about the budget, have you got too many, what’s the competition, and so on. Of course, the fact that Pierce was about to—I think he became Emeritus in 1948—so that in effect, in picking the field of acoustics and in picking this course, I was not unaware of the fact that this was a field in which there was going to be a vacancy at Harvard. Now, of course, Harvard doesn’t honor vacancies in subject matter. They look for people, not subjects. They would not have flinched at allowing acoustics to disappear if they had decided to appoint a more promising person in some other field. But at least this didn’t hurt—the fact that I could provide the continuity in subject matter that had been offered. No, I wasn’t aware of any—I think Professor Chaffee and Professor Pierce both were always kindly disposed toward me.
Beranek:And I suspect, Professor Saunders.
Hunt:Yes, they must have been at least not disposed against me. Chaffee, I think, may not have been—I don’t know whether he would have been a strong—whether his voice would have carried heavy weight with the administration. To some extent I have the feeling that this was a period, and one of the relatively rare periods, when the situation at Harvard could sort of just grow in the subject matter. We try to take some pains nowadays to keep this from happening, and when I think of the ad hoc committees and the procedures that are used now for the scrutiny we give new appointees, I’m glad it happened back then.
Weiner:While we’re on this subject, would you care to comment on the place of the science faculty at Harvard in that period as compared to the total picture of Harvard?
Hunt:Of course, Conant was President of Harvard in this period, and he was a scientist. Science was respectable. Engineering was not particularly respectable then any more than it is now. Engineering has always been the poorer relation, so that I think Conant probably felt that there were vested interests—of course the Gordon McKay endowment for applied physics was sitting there—to support engineering. He wasn’t about to turn this over to somebody else, so that engineering was tolerated, and allowed to live live on its Gordon McKay endowment, but it didn’t have at Harvard, I think, the respectability that pure science had—either pure physics or pure chemistry. The status of pure chemistry versus applied chemistry—Harvard has never had a chemical engineering curriculum—they spurned the title, spurned the name. They teach chemistry. Chemistry is chemistry. If you choose to do some of it in engineering work, fine, but its still chemistry as far as they are concerned. This is about all I can say. Of course, Conant became involved in a great deal of applied science during the war—his work with Compton in setting up the artificial rubber, the synthetic rubber program Conant could come to grips with what you might call the practicalities of engineering, but he was the scientist and as far as Harvard was concerned, it was science that got support, not applied science.
Beranek:Where was your work done? Where was your office and how did it relate to the more pure physics that went on?
Hunt:Last time I was confused and I still haven’t straightened out in my mind exactly when I moved into Professor Pierce’s office in the corner of the second floor. I know was there when the war started and at least for a few years prior to that. This was on the second floor of Cruft and my office was in Cruft until we moved out to Hemenway during the war with the Underwater Sound Lab.
Beranek:In other words, Professor Pierce moved out of the corner.
Hunt:Yes, he moved into Lyman and I moved into his vacuum.
Beranek:The corner we’re talking about is the one that is nearest the Peabody Museum.
Hunt:Yes, the northeast corner of the second floor.
Beranek:Now the pure physics was not in that building. Cruft was sort of the electronics part.
Hunt:Cruft was Cruft. It was still Cruft then, that is, Cruft still stood for a program of education in applied physics that is halfway between physics and engineering, primarily electronics and communication. It preserved that identity and it was not until after the war that the double registration, double support, and so on, got simplified.
Weiner:Can you clarify your title in the period as Assistant Professor of Physics and Communication Engineering?
Hunt:This was because these were joint appointments in the department of physics of the faculty of arts and sciences and in the graduate school of engineering. The graduate school of engineering taught communication engineering. So that faculty members in Cruft had the phrase “Communication Engineering” in their title.
Weiner:Where did your students come from primarily?
Hunt:A mixture, some from—the same course was listed in the catalog as Physics 26 and Engineering 226, and your class list had 6 names with physics and 6 names with engineering, so that in the same class the grade sheets went to two places and the course description was duplicated in the two catalogs, but it was the same course.
Weiner:Perhaps this could be a good time to follow this up and inquire about the size of the class, the relative response from these students from different backgrounds, and, in fact, what did you teach?
Hunt:I was teaching the acoustics course, with what you might call occasional support excursions to fill in when Professor Chaffee was on sabbatical, in his course on vacuum tubes and in the course in circuit analysis. I taught those two courses occasionally. Then we had two half-courses in acoustics. During the period up to 1940 I was teaching these two courses in acoustics—one inherited, from Professor Pierce, the other half-course that I’d started myself—helping Chaffee occasionally and supervising the laboratory work for all of the Cruft courses. At some point along the line Jim Shepherd stepped in and was the laboratory supervisor and I think this may have been the time when I got my load cut down to teaching just the acoustics courses.
Beranek:It was about 1936 when he took that over because he was the laboratory supervisor as far as I remember when I came—I think the first time was the fall of ‘36.
Hunt:The classes then were commonly 15 to 30 people and our student population I would guess was probably two-thirds from the engineering school and one-third from physics, and mostly consisted of students who came to Harvard “to study electronics.” They didn’t know just what electronics meant because not many teachers offered it. There was seldom in the undergraduate electrical engineering curriculum more than a half-course in communications or vacuum tubes and very few physics departments taught it, so that if a graduate student wanted to study the electronic arts, he came to Harvard. Now, we gave a course in circuit analysis and in vacuum tubes. Professor Pierce gave a course in radio waves and he [the student] usually had one course left over. Many of them would sample the acoustics course for, in effect, technical distribution, for broadening. This is the way Beranek got into this game. He didn’t come to Harvard to study acoustics but he took acoustics as a fourth course, and out of 15-30 in the class who were taking it as an extra course, we would sell the fun of the subject matter to enough people that they became the recruits for our doctoral programs.
Weiner:When you first met them in class, at what level were they in their graduate work?
Hunt:Usually they were first—year graduate students. This course was commonly taken by first-year graduate students, occasionally a man would have room in his program for an extra course in his second year in the graduate school, so they were mostly first and occasionally second-year students.
Weiner:Did you teach undergraduates during this period?
Hunt:Advanced undergraduates could also take it. They were seldom more than 2 or 3 out of 20 or 30.
Weiner:But you had no course that was specifically offered?
Hunt:No, Professor Saunders used to give a course for undergraduates. I have consistently, from back in those times, opposed the offering of acoustics to undergraduates. It seems to me that this is not an undergraduate subject, much as I love acoustics. Strangely enough, this is a self-defeating argument but it is one that is logically consistent. If you want to practice acoustics professionally, then you should spend your undergraduate career, I say, getting the intermediate courses in physics, thermodynamics, fluid mechanics, elasticity, more math, more math and more math—not acoustics. Then, at the graduate school, after you have these ingredients, you can synthesize these together into the subject matter of acoustics. The only person who should take acoustics at the undergraduate level is a man who isn’t going to do anything with acoustics after he gets his bachelor’s degree. If you could limit an undergraduate course to those people, I would see it as a harmless type of technical distribution, although even for them I think it might be more valuable to get some firm foundation in thermodynamics or solid mechanics. The effect of this is that you do not have any opportunity to inspire undergraduates to pursue this as a graduate subject, so that the only opportunity you have to sell acoustics to the undergraduate is in the role of an adviser. This, I think, is the current ill in the recruitment of students in acoustics—not enough of the people who advise undergraduates in physics departments and engineering schools are aware of the fact that acoustics is a good subject for postgraduate study.
Weiner:In this connection, have you ever taught a general physics course for undergraduates?
Hunt:Not since 1929 when I had an excursion at teaching this at Radcliffe by way of picking up some money on the side. I mentioned earlier my brief excursion at teaching physics at Ohio State and since then I’ve been almost entirely concerned with graduate courses. During this period of the 1930’s the Cruft staff had responsibility for the laboratory work for the junior course in electricity so that I have been involved in the undergraduate course in electricity, but not otherwise with general physics. Personally, I think this is welcome to me but you do forego the opportunity to allow your enthusiasm for the graduate subject to infect some of the youngsters.
Weiner:A final question on this before we get back to the mainstream of the acoustical research and this is something which may lead into it—what about the relation or the correlation between your teaching and research, in terms of time, in terms of the compatibility of the subject matter, and of perhaps the frame of mind required, and also how this related to the graduate students themselves?
Hunt:I’d like to use Beranek as a test case in answering this question. I have the feeling that I have always taught my graduate course in acoustics from the point of view of doing research in the subject. When I look back, the course outline hasn’t changed appreciably in the last fifteen years, but what I say has changed a lot. The things you use for illustrations of what goes on—this is keyed to the status of research in the field, and the problems—you stop here because it is difficult to go on. You point out to people as you go by—there is a thesis in this for somebody one of these days, in the same way that when I do sound waves in a tube, I stop at one point and say, “This is the place where Beranek went ahead and made a thesis out of it. You can read it in the library. We will go on to something else now.” This is perhaps the way that graduate courses ought always to be taught. There have been lots of philosophical discussions about applied science versus engineering versus pure science. Immediately after the war when we were talking about the reorganizations of what used to be Cruft—I won’t try to go through the organizational steps, but first there was a Department of Engineering Sciences and Applied Physics (DESAP) and for example, Professor Berry, who joined this group, had taught a course in thermodynamics the year before as an engineering course. Now one year he was going to teach it as a course offered by the Department of Engineering and Applied Physics. He didn’t see any need to make any change in the course outline. The question was: what difference was there in the course? There was a big difference because Berry was teaching it with a different motivation. He was trying to teach now a course for students of engineering science and applied physics, not a course for engineers. The students hadn’t really turned into one or the other, but the professor’s attitude, his motivations, had. And I think this is one of the very important intangibles—you never can find this in a college catalog, you can only find it in the students that have been through the mill. The same conclusion reads on the distinctions between applied physics and quote pure physics. You can watch a man in the laboratory, doing an experiment, and you can’t tell by watching him whether he’s doing an experiment in pure physics or whether he’s doing an experiment in applied physics. The only way you can tell is to ask him why be is doing it, and it is his “why” that makes the difference, not the objective things he does. I think this carries over into the teaching. Does this answer your question?
Weiner:Yes, and it leads me to more.
Hunt:We could spend the rest of the afternoon on this and if we don’t look out we will.
Weiner:I will just ask one factual question then: did you feel a time conflict between the teaching and the research functions of your position?
Hunt:Oh yes, you always do this. It depends on whether you are conscientious about your teaching. I’m not fast in the head. I can keep my nose above water because I don’t need much sleep so I can spend longer working some of the things out. But if you’re conscientious about your lectures, you have to spend time on preparing the lectures. After giving the same graduate course for almost twenty years, I still spend 2-3 hours in preparation for each lecture, and this is time that you could have been spending on research. So there’s always this conflict and at least I feel that, in my present situation—I have a long gray beard now, I’m a senior—the graduate courses in acoustics that I’m teaching, this is the way I have to recruit my graduate students, this is the way I have to recruit my research men. If these boys are going to be research men, then I want them to get this fundamental stuff very firm, and the only way I can do that is to review it myself. This takes time and this is part of what you do when you’re a teacher instead of going to work for a firm like Beranek’s consulting outfit. Yes, there’s a conflict but I am perfectly happy to accept this. You do the research with all the rest of the time that you’ve got that you don’t have to spend sleeping.
Beranek:Hay I make some remarks on this point as a student, so we can get them in relation to Ted here—first of all, when I took the course, 226A & B, Ted did a remarkably good job of teaching. His lectures were well planned, they were enthusiastic, the class was with Professor Hunt, I should say, every minute. He was our Professor and we enjoyed it. The laboratory experiments that were associated with the course were very well worked out, and, as I look back on them, were certainly ahead of anything in any other university in acoustics. They were modern, they were to the point, they dealt with matters of hearing, with measurement, with acoustic devices of one sort or another, and I think it was one of the best courses that I took in my entire stay here at Harvard. Now, one thing I think I ought to mention about my attitude toward Ted’s method of training: there was some contrast between Ted and Professor Morse. Morse approached everything as an extension of the use of mathematics, in other words, he thought of the math and then found applications for mathematics. Ted’s attitude as I saw it as a student was: how do we solve this vital problem that nobody else has worked on? And Ted’s ability to use electronic equipment and to visualize the problem and to visualize how to solve it came first, and then you saw later the application of mathematics. He brought the math in after he visualized where he wanted to go. Ted may not feel this is true. Would you like to remark on it?
Hunt:I listen with interest and have no objections to your conclusions.
Weiner:A point raised there: who devised these experimental demonstrations that accompanied the acoustics course?
Hunt:We worked them up. I think this is a “we.”
Beranek:When I took it, they were here already, but my impression was that they were the outgrowth of Ted’s papers that he published, or in the howling receiver case—this is the one you did with Cliff Mel, wasn’t it?
Weiner:We’re pausing now to change the tape…This is the beginning of the second reel of tape.
Hunt:In response to your question about Cliff Mel—I hadn’t remembered that he was a lab assistant at the time. The way we commonly devised these experiments was that somebody, and I suppose that was most often me, would say, wonder if you could do this? Why don’t you see if this would work, maybe you could make a lab experiment out of it. So he went in and set up some equipment and sure enough, it worked, and so he made a laboratory experiment out of it and we ran it. This was the way most of our experiments were devised. The first lot of them, of course, the reverberation stuff, I had done, was a carry-over from my own thesis work. Or some of it fed back the other way, I tried to do it in the laboratory and it didn’t work very well, so I made a thesis out of it. But when Dr. Hickman and I were both in the laboratory, we commonly did experiments for the class that had been published as research jobs two or three years previously. I remember we set up a thyrotron circuit for realizing in practice a constant potential cathode in order to do initial velocity of emission experiments for Chaffee’s course and someone had published this as a research paper, I think the year before, and we said this was a neat way to do it and we ought to be able to devise this, so we did and we ran it as a laboratory experiment the next year. So that this was the way these things evolved; this is the way they still evolve. We used to say that the people we really trained were our lab assistants, they were the people who got the training and the year or two that the student served as a laboratory assistant was, far the most valuable real training they got.
Beranek:Ted, I want to go on now to one subject which, I believe history will record as one of your most important contributions, although perhaps your contributions to the war effort were more important, in reality. And that’s this whole subject that led me to believe you were the noisiest man in the staff at Cruft by the sounds that emanated from the fourth floor.
Hunt:Yes, the phonograph story. This is a long story that’s still going on. It started in 1936 when someone asked me if we could make some recordings of the Harvard tercentenary exercises. They were going to make some sound on film but they thought it would be nice to have a backup of some disk records, could we make them? Well, we gulped and said we guessed we’d try and so we set out to assemble some equipment to make these records. Jack’s role in this was invaluable; not only was he a skillful electronicer, he was also skillful with his hands and it turned out that he was the one who actually ran the recording lathe and made the records—even then I was operating by the method of instigation rather than perpetration. So we made the records and had a number of trivial adventures in the course of this. In the course of assembling this equipment, we got the best pickup—playback instrument we could and we tried to equalize the system as well as we could. After we’d made the records of the actual proceedings, we didn’t want to play them back right away and so we investigated further the conditions under which we’d made these records and we discovered that our pickup was woefully inadequate and that in order to try to compensate for it we had inserted a tremendous amount of equalization and so we had recorded a lot of high frequencies on these records that we could not, at that time, play back. And we scouted as far as we could and finally, within about a year, came to the conclusion that if we wanted a better pickup we had to make it. So we said, well, why don’t we try? And this started a long series of what would call whydontcha sessions, whydontcha do this, whydontcha try this, and we would have one of these sessions and then Jack would go off and bend up some wire and we would try it. And this gradually became a little more sophisticated so that by the end of 1937 we had a lightweight phonograph pickup that was far superior to anything on the market. At that time phonograph pickups operated with two to six ounces bearing on the stylus and ours would play at 5 to 15 grams, about a fifth to a half an ounce and this was a tremendous advance. And so we prepared and eventually published that fact. Paul Donaldson, you may remember took a photograph of this pickup and a record with a nice diffraction pattern on a cover of Electronics magazine.
Beranek:I remember this. This was in the days when Electronics was about three-sixteenths of an inch thick.
Hunt:Yes, and to make the cover of Electronics was good and Paul was delighted with getting his photograph on it and we were tickled to have our pickup on it.
Weiner:This was in March, 1938, and the name of the paper was “A Radical Departure in Phonograph Pickup Design” which was co-authored by J. A. Pierce.
Right. HP6A. H-P was Hunt and Pierce. Well, in the course of our experiments with measuring the frequency response of this, Jack began to worry about the geometry and Jack has a knack with geometry and he was the first to realize, that is, he preceded me in realizing that if a sphere rolls or slides along a sine curve its center does not trace a sine curve. The most of its center is not sinesoidal, not unless the sphere has a vanishingly small radius. And so, since the tip of the phonograph needle is presumed to be spherical, this is a source of harmonic distortion. And so we set out to analyze this and at the time the best we could do was to write a parametric equation, we couldn’t get a closed form. Professor Chaffee, in the meantime, had developed his methods of schedule harmonic analysis in dealing with vacuum tubes, so we set out to use Chaffee’s schedule analysis on our parametric equations and by judicious selection of the number of sample curves for which you computed these harmonics, you could then plot it and take contours and predict the harmonic distortion for the whole range of values of sphere diameter modulation. And so we did this and prepared the paper that came out in early 1938. In the course of working out this parametric equation, we had to make an assumption about how the stylus was supported by the groove wall and we made what seemed to be the only reasonable assumption, namely that it was supported by the side walls of the groove, not on the bottom, and so we analyzed it on this basis.
We, moreover, concluded that that was the way you ought to play the record. That the stylus should not ride to the bottom of the groove, but should be supported on the side walls. That was the only way you could be sure where the stylus was with respect to the groove. And, prior to this time, there were only shellac records available at that time, and always the legend was that there was abrasive in the record so that it would grind the stylus to fit the groove. Actually there wasn’t any abrasive, it was just the clay fillers they used in the shellac, but it did serve the purpose of abrasive. Well, this assumption of side wall support was necessary for the mathematical analysis. It was obviously the proper way to play a record and our pickup was the only one that was light enough to allow the stylus to be supported on the side walls without deforming the groove wall enough to ride on the bottom. So we had conceptioned and reduction to practice, and when we were applying for patents on the pickup we included some claims on the side wall support of the stylus. And the reason I mention this is that this is the fortune that Jack and I eschewed and gave up to the phonograph industry because we both got distracted by war research, the patent came out during the war, and by the time the war was over it had already been late, we had abandoned it, we never sued anybody. If we had been careful about picking some small fellow and suing him and getting the claims validated, I think we could probably have made a lot of money from the side wall support, because by the time the war was over everybody took it for granted that, of course, the stylus was supported on the side walls of the groove, how else would you do it? And without realizing that—in 1938—this was not only novel but no other pickup could do it except our experimental job.
Weiner:Do you have any idea how soon the pickup was picked up commercially?
Hunt:The pickup never was. The side wall support was picked up almost immediately after the war.
Beranek:Could I interject a statement or two here. There was an important paper in the Journal of the Acoustical Society that was presented in ‘40 and published in January, 1941, called “A Theory of Tracing Distortion in Sound Reproduction from Phonograph Records.” I guess maybe that isn’t the same paper. That was with W. D. Lewis.
Hunt:That’s the definitive analysis of the tracing distortion which Lewis did with my connivance and kibitzing, which did get the answer enclosed in the form of a series which Jack and I could only do by this schedule analysis.
Beranek:I guess your paper with Jack Pierce was never published?
Weiner:“Stylus-Groove Relations and Their Influence on Phonograph Reproducer Design.”
Hunt:No, think that’s not the one either.
Beranek:Then there was a paper called “Phonograph Reproducer Design,” with Pierce in 1941.
Hunt:On “Distortion in Sound Reproduction from Phonograph Records,” July 1938.
Beranek:That’s the early one.
Hunt:That’s the early one. Let’s talk about that early one because that 1938 paper is one of the two most important papers I’ve ever given, I think. Or at least I can say we had more fun with that one. Because not only do we have this distortion story and the side wall support, but also the by-product that the lateral recording is a push-pull system. The vertical recording is a single-sided system. A vertical recording is subject to second harmonic distortions, lateral cancels the second harmonic. Well, in 1938, there was a lively competition between lateral and vertical for broadcast transcriptions. Vertical was not available for home use. Home phonographs were all lateral.
Hunt:For broadcast transcriptions there was the World Broadcasting Company who sold verticals made with Western Electric equipment.
Beranek:Called Hill & Dales, weren’t they?
Hunt:Hill and Dale. And, other transcriptions made lateral. And this was a very lively commercial competition. Here we came into a meeting—it was first presented at a meeting of the Society of Motion Picture Engineers—and said Hill & Dale has got all the Second Harmonics; laterals has got the push pull and no second harmonics. And in effect this paper tipped the scales and within a year the Hill and Dale transcription records almost disappeared. They came up with a very neat tour de force in answer that if you re-recorded the Hill & Dale record with the polarity of the recorder reversed, you could in effect predistort the signal and get the effect of the push pull. And so we asked them the embarrassing question, yes, but do you do that in your commercial recordings and this question was dodged, so that in effect this paper shook the phonograph industry. And it was one of the few papers up to that time that had dealt with the phonograph playback process on a physical basis, on what you might call a scientific basis. Jack and I had a lot of fun with that paper. This put us in a unique position—as academics, we had no commercial axe to grind, and therefore we could freely say to any manufacturer, you don’t know what you’re talking about. On a statistical basis with phonograph manufacturers you can make money betting that. And he knew that we weren’t saying it because we were trying to sell something in competition. As a consequence, we could talk with almost all the manufacturers who would tell us what they were doing.
Beranek:In particular, what the other fellow was doing.
Hunt:Because we had nothing to sell, we felt that we had an entre to the professionals in the phonograph business, that we could not have had had we been in the business ourselves. And when it came to electing whether or not we would defend our rights under these patents, we had the feeling that if we did we would sacrifice this position of academic independence and for better or worse we elected not to do so. So we never made a nickel out of our phonograph patents. Although Jack and I used to sit around sometimes and say well now if we got so much royalty this would amount to one million, two million.
Beranek:Ted, with the small pickup which was published as a photograph on the cover of Electronics and a paper inside or maybe later there was a paper. There was a paper on phonographic design also given later on in 1941 with Pierce, I notice.
Hunt:The paper was in that issue.
Beranek:The thing I was going to bring up was, it was my memory that it was not long after this until the first very light-weight pickups came out and the first one I remember I thought was made by Fairchild. Was that right?
What I remember on that was that just prior to the war, I think it was Al Williams, yes, Al Williams, at Brush, now Clevito, made a crystal pickup that would play at one ounce. And this was a special experimental job just before the war. Immediately after the war, one- to two-ounce pickups were common. So in the four-year gap between say ‘41 and ‘45, when the pickup manufacturing business went back to work, they dropped the weights by about five. And we had hoped at that time to get somebody interested in building our little gadget commercially, at least for the deluxe amateur market. A couple of times, we had a couple of nibbles. And just about the time we thought we were going to get somewhere, the General Electric Company came out with the so-called variable reluctance pickup. Now this was about three to four times as heavy as ours.
Not as wide in frequency response. But it was so much better than anything else available that it took all of the steam out of the interest shown in our pickup. So that, although it wasn’t as good as it should have been, it came out at just the time to cut off any chance that we might have had to persuade somebody to try to manufacture our gadget. Of course, since that one that was on the cover in ‘38, we kept on working at it up to ‘41. There are a couple of other things indicated as papers in the bibliography which we described at meetings of the Acoustical Society but didn’t publish; it was good old HP6A on the cover of Electronics in 1938, and the model that was our ultimate achievement was an HP26A. And we’d used all the numbers in between. And in 26A, we had dropped the weight—this would have played at one gram. The equivalent mass referred to the stylus of that 1941 pickup was less than one milligram, and only now are the best deluxe pickups getting down to the equivalent mass we had in 1941.
Beranek:I note in looking over this biography that you gave a number of oral papers right up to 1962 on such things as the Rational Design of Phonograph Pickups. I see that possibly this was published in the Journal of the Audioengineering Society in ‘62.
Hunt:I can fill this in rather quickly. Jack and I worked on the pickup to ‘41. Then he went off to play the kind of radio direction-finding that turned into LORAN. He was one of the co-inventors of LORAN. And I went off to play with airborne military acoustics and then underwater sound. After the war—and it was just in that transition period that Deming Lewis who just has recently become the president of Lehigh University—I persuaded him as a post-doctoral project to have a go at this tracing distortion problem, and he worked this out in what has been—I guess still is—the definitive analysis of the tracing distortion problem for a rigid wall groove. So we laid it there. After the war, I persuaded one of my graduate students, Miller, to go back and relook at this problem, taking into account the finite elasticity of the groove wall. So Miller worked out the problem of the elastic groove wall, and published that. It identified the stylus groove resonance and explained the mysteries of what is called “translation boss”—but this was, again, a nice definitive landmark. And that was about 1950. Then it lay fallow, and about four years later, Ted Schultz, again as a post-doctoral project, helped me with some measurements on groove wall deformation: measuring the tracks left in a groove after the stylus has run over it, which took some nice experimental work with a microscope. So we published a paper on that, “On Stylus Wear and Surface Noise in Phonograph Playback Systems.”
Beranek:And that was in January 1955 in the Journal of the Audioengineering Society.
Hunt:Right. And then another graduate student comes along and in each of these things now, the problem lies for a while and you say: “What is the thing you don’t know about in the phonograph playback process?” And one was: You don’t really know what the elastic constants of this plastic material are. So I sicked Bob Walkling onto—as a thesis problem—can you devise a technique for measuring dynamically the deformation and force applied to a stylus riding over a plastic surface? And you could describe this as a sphere sliding over a plastic surface or you could describe it as a phonograph stylus tracing the record groove. And so he—not very fast—Bob was a slow worker, but he eventually made a thesis out of making some measurements of the dynamic elasticity. So I’d go to meetings of the Audioengineering Society and I’d hear people talk about lightweight pickups that bear two grams on the record. And I would say what do you mean by calling these heavy duty alternaters a lightweight pickup? And I came home from one of these meetings when I’d ventured to stand up and make some snide remarks of this kind and said to myself: Am I pushing too hard, I wonder if you really can make a pickup that’ll play at a tenth of a gram bearing weight, for instance, and so maybe I’d better go off in the corner and find out whether you can or not before I open my big fat mouth anymore. So back around ‘57, I started on what you might call the modern version of building an ultra-lightweight pickup. And at a series of three, I think, successive meetings of the Audioengineering Society, I made progress reports on this, and we have indeed got a pickup that plays at a tenth of a gram bearing weight with good margins.
Beranek:And that paper, if read correctly, was published in 1962 in the Journal of the Audioengineering Society.
Hunt:That was not published—these are the papers.
Beranek:Yes. Well, there’s a series of them as you say.
Hunt:A series of papers. Now in the course of working up this pickup, this piece of hardware, you have to decide what parameters you want, so that you go off in a corner and systematize this; and so I discovered that I had some material on the selection of the parameters of the pickup in terms of the relevant boundary conditions, I mean, what’s the recorded material, and so on. And so this made the subject matter of this paper on the rational design of phonograph pickups, which in a sense is detached from our actual laboratory work. It represents the distillation of what I’d learned about how you ought to build a pickup, quite aside from how you ought to design the mechanical structure of a proper pickup. And strangely—I don’t know whether its strange or not-—but its unfortunately true, that all the commercial pickups are still out of bounds by factors of three to five on what they should be in relation to these things. Some are moving in the right direction. And so I think the “rational design” paper and the oral presentations are exerting an influence on the—they’re nudging the commercial designers in the direction I think they ought to go. And I get some satisfaction out of the fact that I am helping in this sort of indirect way to influence design without being on the firing line and being directly involved.
Beranek:As you ought to mention, you did receive a national award for this work.
Hunt:The Emil Berliner prize: The Audioengineering Society has a prize for this and I guess that was back in ‘58 or so.
Weiner:It’s 1954—the Berliner award.
Hunt:OK, so they were really reading back on our early work. Our work in the 30s was what Jack and I both insisted on calling “avocational”—this was out-of-hours work because it wasn’t supposed to be quite respectable for a physicist to be designing a phonograph pickup. It’s still not clear whether this is quite respectable activity, although I think that this “rational design” paper is a completely respectable activity.
Beranek:Well, I’m sure you’ve made a respectable engineering subject out of phonograph pickup design by now.
Hunt:Jack and I got some amusement and satisfaction out of saying that “Indirectly we had taken (I did some arithmetic and I should have looked the number up) a good many hundreds of ton miles of loading off the phonograph pickups of the nation” since we started pushing on this subject of lightweights back in 1938.
Beranek:That is a marvelous way to put it. Ted, we’d better win the war now. We might start this off by saying that I got my doctorate in 1940 and Ted really was enthusiastic about my getting my doctorate that year.
Hunt:I was going to lose him.
Beranek:He thought I ought to at least work on another subject for Ted in the process, but I said the war might start. Indeed, the war, for us, did start in the fall of l940 when the National Defense Research Committee was set up.
Hunt:NDRC wasn’t set up until the spring of ‘41.
Beranek:Is that right? Well, anyhow, the President authorized the Radiation Lab to start in the fall of ‘40—
Hunt:That was a special committee.
Hunt:That was a special committee, and the National Research Council was asked to do something for the Air Force.
Beranek:That’s right, Wright Field.
Hunt:And that was in the fall of ‘40. And Smitty, Professor S. Smith Stevens, Stanley Smith Stevens, and I attended one of the meetings at the National Research Council when they were talking budgets. And the estimate was that they might be able to spend $15,000 and somebody said you’re crazy, we’ll put the figure in for $45,000. And I think somebody else looked and said: “These boys, these academics, don’t know what they’re talking about.” And I think the first contract went in for something like $90,000. And it turned out to be that that was a much sounder guess than ours had been. Well, do you want to tell that Fall of ‘40 story?
Beranek:Well, we may have different versions of it. But the way that this got started, as I remember it, in some ways created a little friction. And whether Ted wants to talk about this friction or not, I don’t know, I might touch on it enough to show that there was some. Morse got word of this request from the Air Force, this is Philip Morse at M.I.T., who was the head of acoustics down there—through Karl Compton; and Karl Compton was later chairman of the National Defense Research Committee, and I guess was chairman of this temporary committee that was intervened.
Hunt:The Radiation Lab Committee.
Beranek:Radiation Lab Committee. And he asked Morse if he’d work on this. And one evening I received a phone call at home—and I lived then right near Harvard in Cambridge—and Morse wanted to know if I would come to M.I.T.—or would do the work at Harvard—necessary to investigate ways of absorbing sound, meaning reducing sound better in aircraft in flight.
Hunt:This was fall of ‘40.
Beranek:Well, it was early fall then, it was probably September. And I was flattered by this. I had received my doctorate in the spring. And Morse had been very appreciative of the published paper that followed my doctorate and that’s the reason he called me. And I came back and reported to Ted that I’d received this call from Phil Morse and that he asked me if I would take on the job of being Morse’s assistant to do this work. And I had the feeling that this upset Ted considerably because he felt that if I was going to do it—particularly if I was going to do it here at Harvard—that Ted ought to be the director of this. And Ted, I think, pursued this point with Compton. And my version of this…
Hunt:I never talked with Compton about this.
Beranek:You didn’t? I thought you went down to see him.
Hunt:No. Never with Compton.
Beranek:Or wrote him a letter. But anyhow I thought you had—you did with somebody.
Hunt:Must have been Phil.
Beranek:And the upshot of this was that Compton said, “Well, it wasn’t a very big job anyhow and why not let me run it alone?” That’s my version of it. As a result—and I tell another version of the story you just told. I think it’s the same one. I was asked to prepare a budget and a committee was set up to supervise me which both Professor Morse and Professor Hunt were on—they were on this committee—and I set up a budget for the first year which did not include my salary because Harvard was paying it, for a little over $2,000 and I have that budget at home still. And we went to this meeting which was a little job that I had been assigned and was now going to run alone with my budget and the military showed up there and I presented my budget…
Hunt:Do you remember where this meeting was?
Beranek:Yes, it was in the Flatiron Building in New York. It was where the American Institute of Physics used to have its offices right in the end of the Flatiron Conference Room.
Hunt:I didn’t attend that.
Beranek:Yes, you did.
Beranek:Yes, you certainly did. And Morse was there and Hallowell Davis was there, Stevens was not, and also the military, and the discussion went on. I have minutes on this I looked up...
Hunt:Do you remember the date of this?
Beranek:It was in October, early October, l960—1940, I’m sorry—twenty years wrong. And I presented this budget and there was great silence in the room and then Fred Bent stood up and said, “Well, if you’re going to talk in these terms, you might as well go home. If you want to multiply your numbers by ten, we might be willing to talk about it.” And then he said, “Furthermore, we’ve got to set up a study on the psychological effects of noise on man and that ought to be matched and we should find somebody to run this.” And we ended up with $45,000 for me, $45,000 for the man who would be selected to do the psychological experiments and then, finally, Bent said, “If you’ll spend it in a half a year it will make sense.” And so, we went out of there, effectively, with “180,000 operating rate and you, Professor Hunt, and Professor Davis were given the job of seeing if S. S. Stevens might consider running the psychological part. Now this, in many ways, although it may have disappointed Ted at that time that I got the big job so soon, led the way for Ted to enter into the really important job of the war which was licking the submarine threat.
Hunt:Do you remember when Smitty came into that picture?
Beranek:Within a month.
Hunt:Some parts of what you say I remember and a few parts I wouldn’t have told the same way because I didn’t remember. But I have no reason to contradict anything you said. The next stage of this that I reconstruct came early in December and through Professor Bitter at M.I.T. and one of his friends in the Navy, Bitter had contacts with the Navy on account of magnetic mines, and one of the men in the minesweeping department asked Bitter if he could find somebody who would figure out how to make a noise like a ship, so that you could fool acoustic mines. And so Bitter turned to Morse, his colleague at M.I.T., and Morse called me in and said, “Do you think we should undertake this?” And this was the year, you remember, that Dick Bolt had gone to the University of Illinois, and we, Phil Morse and I, said we would be willing to tackle this if we could get Dick Bolt to come back from Illinois and if we could persuade Lou Fussell to join in and we also got John Trimmer started to think about how to make noises that would sweep an acoustic mine, by Christmastime of 1940. And, you remember the great to-do about security, we were investigated and they had time then, there weren’t so many of them so they took the investigation seriously, and I got a very interesting letter from my family, because somebody had started asking questions about me out in Barnesville, Ohio, and everybody that they spoke to in the town, as soon as they left them, would dash up the street to the bank and tell Dad about it. So Dad had two or three people come in and say “What’s somebody asking about what Teddy’s doing?” So I heard about the field investigation from Dad, who heard from all the people in Barnesville that had been questioned about me. So this went on, but early in February of ‘41, we had our first success. This was the parallel pipes, which later got the code name “Foxer.” Do you know the Foxer story?
Well, we wanted to make broad band noises and by this time we had drawn Professor R. D. Fay into the picture, old-time M.I.T., into the picture, and just recently died, you know, and in Morse’s office at M.I.T., we were having one of the “whydontcha” sessions—Morse, Bolt, Fay, Hunt and Fussell. And Fay suggested putting two spheres close together and towing them so that the flow through the center with the Bernoulli effect would reduce the pressure and cause cavitation. And one of us, I don’t know whether it’s wishful thinking or not, but I think I suggested “why not make them cylinders so that you get the whole length.” So we were making sketches on the blackboard, and this went on for a little while and Lou Fussell said, “Well, you fellows go on and talk about this a while, I’m going out in the shop and make one of these.” So Fussell disappeared and went out and got some two-inch water pipes and bolted them together on the end with some washers to hold them apart and rigged a rope and the next day we took this out in Boston harbor.
We had already installed a sound range off Gallops Island in Boston harbor and we had the Navy tug Wappashaw, which was our vessel at that time, skippered by Don Hodges, who later became skipper of the underwater sound lab ship Galaxy. So, Fussell rode the tug and had a walkie-talkie, we were on shore beside the monitor and they cast these over the side of the tug and the tug started down the range and a terrific clatter broke loose out of our sound monitor. We all blinked and looked at each other and said, “Are we causing that? Or is something else going on? Is there a loose connection, or what?” So they finished the run and we got on the walkie-talkie and said, “Something very strange is happening, but we’re not sure what it is. When you make your return run, just as you get over the hydrophone, drop the tow, and we’ll see what happens.” And so the Wappashaw came back, clattering all the way, and over the hydrophone they dropped the tow and it stopped. So we had really made it. We didn’t know what we had made, but we were trying to make some noise and, well, we sure did. So, by the time the Wappashaw finished this run, the pipes broke.
So the experiment was concluded and we all picked up and went home to decide just what had been going on. And the answer was quite obvious; we were talking about producing a pressure drop in cavitation, we didn’t think about the fact that the pressure drop would bend the pipes and make them bang against each other. And, sure, that’s what happened, the pipes would bang together and that would stop the flow, and then the elasticity would make them spring apart again, then the flow would create the lower pressure and pull them together again. So, we had a relexation oscillator and clanging pipes. Well, we wanted to make a noise, so this was highly successful. From then on, it was really a case of mechanical engineering to keep the pipes from breaking themselves due to fatigue, and to fix a harness so that you could hold it. Eventually, in due course, this turned into a neat little thing about five feet long, about three-quarter-inch pipes that was light and could be tossed over the stern of a destroyer and towed and they refined this to the point where they would last a good many hours before they would fail and this swept a lot of acoustic mines during the war.
Beranek:I’ll be darned.
Hunt:And the story is told that Dick Fay, the next weekend, at his home in Nahant, noticed he had a little brook running down beside his house. He went up and got a couple of quarter-inch curtain rods and tied these together and held it with a string in the stream and got a fine oscillation just with the two knots stream of the little brook. Well, the Navy man who had been with us observing on this expedition, decided that all of a sudden these scientists weren’t just fooling around making measurements, they had produced something. And the Navy within a week took a completely different attitude on security. Now they had nothing to protect. So, we learned about security when they had something.
Weiner:Was this ever published in any form, later?
Hunt:The anecdotal part of it that I have told here, I don’t think has been published.
Weiner:I mean the actual principle, that was involved.
Hunt:Oh yes, this is in Navy reports.
Beranek:And again in the NDRC books on underwater sound.
Hunt:I’m pretty sure it was. I’ve got a brief mention of it in our HUSL final report, but I’m pretty sure it was, although I can’t put my finger on it. I wouldn’t tell you where to put the finger on it.
Weiner:I ask this because yesterday we were visited by—his name is Klein, I forget his first name, from Naval Research Laboratories.
Weiner:Yes, he’s doing a history of their labs and he was asking for information that could be of help in that project.
Well, to go on with the story, this minesweeping project was located at M.I.T. and very early, by the spring of ‘41, Cyril Harris was drawn in and he was attached to that project for the remainder of the war. And Morse pretty soon got diverted; in due course, Dick Bolt got diverted; so that Harris wound up being the chief custodian of the minesweeping project. During the early spring of ‘41, NDRC was formed, and one of the things that NDRC looked at was something about submarines. And division six—NDRC sort of sprang immediately into a dozen or more divisions and division six was the anti-submarine division and they decided, again very quickly, that there should be a laboratory on the east coast and a laboratory on the west coast. And this was when Tim Shea was brought in to organize the east coast laboratory and Knudsen, I think, was the first one to organize the west coast effort. And the west coast effort was done under contract with the University of California at San Diego, and the east coast laboratory was under contract with Columbia. In the early planning of this, I more or less came into the councils on Morse’s coattails.
We were in because we had already had our ears underwater for almost six months with the minesweeping project, so we had built hydrophones. And this was more than the people in NDRC who organized the new laboratories had done. So we had a stake in the game. This was our table stakes, as it were. And so, at this point we said: “We’ve had our ears underwater, we can do something in Cambridge on this. How about dealing us in?” Well, at that point the Cambridge effort did not represent a very large diversion of what they had planned for the east coast and so they backed us to go ahead. Well then, Morse and I had the problem: Okay, Cambridge, but where in Cambridge? Since the minesweeping project with underwater acoustics was already at MIT, I said “Okay, let’s put this one at Harvard.” So the NDRC underwater sound project came to Harvard under my wing. At this point, and this is what I thought you were talking about, Tim Shea, I think, wanted to involve you in the New London venture.
Beranek:That’s right. Or you.
Hunt:Yes. And when you spoke about a conflict, this was the one I was remembering—I had forgotten about whatever conflict there was in October of 1940. What I remembered was our discussions of this question in May of 1941. And by this time, your project for sound absorption, sound control, had gotten big enough that it looked clear that you should go ahead and do that—unless you went to New London with Shea and left the airborne sound orphaned, you should stay with the airborne sound, I would take under my wing the new NDRC effort in underwater sound.
Beranek:Well, I didn’t see the second one as a conflict. There was only one day that you and I might have been in conflict and I was very serious about it; and that was when Tim Shea called on the telephone and said he was coming to Boston and tried to get a promise from you and me that one or the other of us would go down there. Do you remember this incident?
Hunt:What I remember was that he invited you to come down but I didn’t remember that he invited me too.
Beranek:No, he invited both of us to go down—one or the other—he didn’t seem to care much which. And I kind of weakened on the phone and said that one or the other of us would do it, that if you wouldn’t do it, I would. It seemed like this became a little disturbing influence to you because I had sort of committed one or the other of us and I felt that this didn’t make you very happy. And then I backed out, which then kind of put you on the spot; and how you extricated yourself I’ve never been sure.
Hunt:Well, it must have been by saying “Okay, we’ll do it, but won’t do it at Harvard, won’t do it here.”
Beranek:There was a little friction over the fact that I committed us and then I had backed out.
Hunt:In all events, by June of 1941, we were undertaking, at Harvard, some work under NDRC sponsorship, in underwater sound. And you and I populated Cruft during the fall of 1941 and into the spring of 1942. And by the very early spring of ‘42, it had become clear that Cruft wasn’t big enough to hold the two of us.
Hunt:By this time I had been doing my recruiting; you had been doing some recruiting; by this time Newman was here.
Beranek:And Chaffee had a project, also adding to the crowd.
Hunt:Yes, it wasn’t a very big one, but he had one on infra-red and thermistors. So, in June of 1942, the underwater sound venture moved to Hemenway, which is across to the west a building and a half.
Hunt:A gymnasium. Hemenway comprised two layers of squash courts and a basketball floor. And we found that a squash court had a high enough ceiling, it also had a mid-level balcony viewing area, so that by horizontally bisecting the squash court, you got four floors and the basketball floor was the fifth floor. And so we took this over and some of the workmen almost wept at the idea of sawing some of those beautifully laminated squash court walls. But we took over and converted Hemenway and made this into the underwater sound laboratory.
Beranek:And again, I think this was a very wise decision—that you got a bigger space that way.
Hunt:Yes. Well, by the end of June ‘42, it was officially designated the Harvard Underwater Sound Laboratory. This was the end of the academic year ‘41-‘42 and this is the point at which Harvard officially relieved me of teaching duties, so that I was relieved of teacher’s duties and appointed by the Corporation as director of this laboratory in July ‘42, which has led to some ambiguity in dates, because I had already been directing the thing for a year and a half before that. Then, with this cleared out it left you more space, and in due course, you expanded into Lyman, and then the electronics training course took up some more space and so, that’s your story. My story, is in Hemenway. Let’s see, we’ve got recruiting, we’ve got laboratory administration, what do you want to…
Beranek:And then we should get what you did. We’d like to know what you accomplished.
Hunt:Yes, what the laboratory did.
Weiner:Can you evaluate how much of this you want to be public?
Hunt:Are we on the record now?
Hunt:We will jump to the end, the laboratory flourished. We spent a total, during the war, of just a shade over seven million dollars. The peak employment, I think, was 462 and, of these, there were more than 150 with a Master’s degree or better, I think. At least, 150 with a bachelor’s degree and I think there were some 50 Ph.D.’s. And there were at least ten of them on the ranks that were being paid more than the director. We were not at all rank conscious. We had people with Bachelor’s degrees supervising and bossing Ph.D.s, and this nobody balked at. The radiation laboratory had been there before us. Oh, I meant to mention, your airborne sound project started earlier, so that you got all of my graduate students.
Hunt:So that when I started to recruit for underwater sound, I had only, I think, Bob Watson, and Charlie Morrow. All the rest were on your show already, I think you had taught the course during that academic year ‘41-‘42.
Beranek:I taught one semester of it.
Hunt:I may have taught part of one of them, but to all practical effect, any graduate student who showed up in the fall of 1941 who was educable at the graduate level, we said, “We can’t afford to let you waste your time taking courses, come and work for us.” And the only people that we allowed to take graduate courses were the people who were not clearable for one reason or another, who either had relatives in Germany or were foreigners or for some reason were not clearable. And so that graduate training at Harvard, in acoustics, disappeared for this period to all practical purposes.
Beranek:I must tell a little anecdote on recruiting because we were in this together. At some time, just about the time that Terman was forming the Radio Research Lab, now when would that have been?
Hunt:That would have been about ‘43.
Beranek:Was it that late? We got together, or the University at his request, got together all of the possible recruitable young people over in Jefferson Lab and they almost filled the room. I can’t tell you who all was in there. There were a lot of young people. And each of the existing war labs was to give a presentation. Well, Terman was the worst off because he couldn’t tell what he was doing or couldn’t even name the field. And he played around with ways of telling them how secret this was, and how important it was.
Hunt:You can say now that what the field was was radar cutter measures.
Beranek:Radar cutter measures. And Ted gave a little talk on under water sound and how important it was in the submarine effort thing, I believe. Maybe not.
Hunt:I suspect that Boner may have done that.
Beranek:That Boner did this probably. And then…
Hunt:I don’t remember.
Beranek:The Radiation Lab came up and had a representative and I was the last one who was tolerated because they had to give everybody sort of equal time as they say in the political television today. And I made out very well in this by simply saying all these people talked about how big they are and everything and reminds me of the convention of the railroad operators. And the one little railroad wanted to have equal vote with the New York Central and the Pennsylvania Railroad and so on though it was only a mile long. And he pleaded his case on the basis that he was just as wide.
Weiner:Was Paul Boner whom you mentioned up here for the project?
Hunt:I pulled him out of the University of Texas along with about six or eight of his graduate students in Texas, and in general in recruiting, the Radiation Laboratory had in effect skimmed the cream of the physics departments in the big schools—they were after the experimental nuclear physicists—and they turned out to be very useful and they were very convertible. So we worked the smaller colleges. Francis Bundy I got out of the Ohio University—after he served with us, he’s the one who helped G.E. make diamonds, you remember. One of that team. Hugo Schuck I got out of C. G. Conn. Recruits were where you found them.
Beranek:Then one of your most illustrious recruits was one of your Associate Directors.
Hunt:Eric Walker, who’s now president of the State University of Pennsylvania was in the engineering department at the University of Connecticut at Storrs. One of the interesting phenomena at least to me was that many of these people that recruited out of small schools in effect had an opportunity in the laboratory to work with facilities that had not been available to them beforehand and they grew and they never went back. So that you had the feeling that by recruiting you were changing peoples lives in a profound way. And hope these changes were beneficial, mentioned that we were not class conscious in the laboratory as a whole. The whole structure was held together by inspiration and devotion. I’ve never been associated with an effort in which wholehearted devotion to the war effort was such an important motivating factor. One of the best recruiting tools was the daily newspaper with the headlines about how many ships had been sunk. And when you went to talk to somebody you laid the paper on the table and said were trying to do something about this. Do you want to come help? And it was heartening to know the extent to which this really moved people. As an organization it wouldn’t have held together for 20 minutes under peacetime motivation. We weren’t paying the kind of salaries, there wasn’t a great deal of organization, there weren’t the opportunities for advancement and so on, that motivate a peacetime organization, but the boys rallied and did a job.
Now could you outline your principal big projects?
Yes, jumping to what was accomplished, we directed our attention early to what could be done to improve the equipment that was already installed on the ships. The New London Laboratory more or less tried to design new equipment from scratch. We concentrated on what you might call add-on bolt-on black-box additions. In this connection we developed the split-lobe comparison methods, bearing deviation indicator, which saw a lot of service and which enhanced the performance of the destroyer sonars very materially. Incidentally, I coined the word sonar.
Beranek:Oh, really. That’s very interesting.
I didn't invent sonar. Echo ranging was an old art, but the word sonar — that was my word. And it had an interesting background. We devised it originally to attach to one of our particular apparatus developments. But I knew this was too good a word to spend on our specific piece of hardware. So somewhere '42 or so the Navy enlisted men—there was more glamour to applying for ratings as a radar man and we heeded something to glamorize the job of the sound operator. So, with the connivance of Chris Engelman who you may remember...
I certainly do. He was a commander, and later a captain.
Yeah. Chris was in the Bureau of Ships at the time and he talked to me one time about how could we make the job of sonar operator sound more glamorous to these people. Well, you need a name. So I sold him sonar. And Engelman wrote the letter which got passed up the line establishing sonar as the designation for underwater sound locating gear. Now, at the moment, the acronym escapes me—we had the word and then we invented the words from which it was to be derived. And he had a different set of words than I had originally.
Weiner:Where did the word come from?
Hunt:Phonetically it was an analogue of radar. This is sound. This is sound radar. It’s as simple as that. When you think sonar and you juggle the syllables and what sells it is the fact that it is euphonious. And this I found is the key in coining words. See we’ve got three words now. “Cascode.” Jack Pierce and I invented the word “poid.”
Beranek:Yes, I remember that.
Hunt:The poid is the curve traced by the center of a sphere rolling on a sinusoid. This turned up and we said this is a very simple curve. It must have a name and we went looking for it and we couldn’t find it. So first we called it a pierceoid and then we said that’s too long, and we called it the poid. So we did. Amusingly, the I.S.O., International Standards Organization, was working up a glossary, and they’d come onto “poid” and I got a plaintive letter from a French secretary saying that could I help him about the etymology of the word, “poid” which he’d been looking up in the dictionaries and couldn’t find.
Weiner:When was the first publication of the word, “Poid?”
Hunt:In our 1938 paper, the Pierce-Hunt paper. We defined it in that report.
Beranek:I remember the birth period of this. I was around.
Hunt:Well, at any rate, as I say, SONAR was a good coined word. I mentioned B.D.I.—we actually manufactured on the Hemenway premises about 300 of these, I think. Or at least, more than a hundred. And then it was subcontracted and these eventually got on all destroyers.
Beranek:I have often wondered how you were able as a non-, or I should use, almost, the word “in-experienced,” inexperienced constructor of anything, having been a professor and having thesis students only, how did you organize so effectively to build things? I was very impressed when I later came in and hired away some of your men when the submarine threat was over and you were sort of closing down by the very fine group that you’d assembled to build things: It was a very good job.
Hunt:Well, I don’t know that I can take much credit for that; you pick a few people and then back them to do what they think ought to be done.
Beranek:Well, but you had to pick these people. Is this an accident?
Hunt:Well, no, we got a very smart man out of NBC, Lou Hathaway. Lou had had a lot of experience at NBC in their engineering staff, and they constructed things. So Lou understood this. And I guess you get somebody, and he says you ought to do this, and so you back him to do it. We had a personnel man and pretty soon he did some of the recruiting, and, say, the shop is not doing something, so we push them. And you push everybody, and they go help you find people. They tell you what you want. As I say, I didn’t know: they told me what was needed.
Beranek:Well, see, our lab went on the subcontracting route. We let sub—contracts for this kind of thing.
Weiner:You mentioned recruiting—can you give us an example of the experiences that you had? You mentioned to me your experience at Case Institute of Technology—if that’s not the best, then perhaps you can think of another one that would serve as an example of the experiences.
Well, I remember, one trip to Ann Arbor in which you called somebody that night, he came in for breakfast the next morning, and so you peddle your wares and get a new man on the books before you take the plane that morning. Ted Smith, who was one of the practical-minded sort of people that wound up running one of the shops, I interviewed between planes at an airport. The incident at Case I told you about—well, one thing I learned early in the game in visiting the small colleges: and that was if you call in the Chairman and ask if he will let you interview some of his assistant professors, some of his instructors, then you may get a chance at some of his graduate students. So I had already learned that you call on the Chairman of the Department and offer him a job; he is always with his roots too deep to consider moving. But since you’ve offered him the job, he will let you talk to some of the Associate Professors. And this was an early lesson in starting at the top. Once in a while, you may get one of these fellows, and that’s all right, too.
We found out for example: we were in the acoustics business in a way, but if a man knew acoustics but didn’t know any electronics, there’s only one place you could put him and that was in the transducer section. If he knew electronics but not acoustics, you could teach him what he needed to know about underwater sound in two weeks: and then you had a man that could do anything. This was because the jobs were mostly how you devise apparatus to do the simple things that you need to do. Simple things—say, you’re going to send a pulse and receive an echo. What do you do with the echo? How do you display it, and so on? And how do you produce the power? This wasn’t simple, then. So that this was an education on the value of acoustics training: the answer, is you got to know more than just how the sound waves work to be able to deal with applied acoustics, and we learned also that you have to spend a substantial fraction of the laboratory effort on transducer design. Because every new idea that somebody gets calls for—somewhere the interface between the medium and the electronics machinery is a transducer—and it’s always different.
But one of the things that the Underwater Sound Laboratory did was to lay the groundwork for the design of magnetostriction transducers. What little art was known was almost proprietary to the Naval Research Laboratory and there was no industrial, no peacetime application: because who was interested in making sounds in water? There wasn’t any ultrasonic cleaning industry. And so we got help from G. W. Pierce, that is he made all his notebooks available. He was even then involved in patent litigation with the Government on his magnetostriction patents, so we couldn’t bring him into our game intimately and tell him about all our problems without getting him involved in a conflict of interest. But he did make all of his laboratory notebooks available to us. And then we went on from there and the summary work on magnetostriction transducer development was in one of the big volumes of the N.D.R.C. Summary Technical Reports and is still probably the bible for anybody that wants to start from scratch to build magnetostriction transducers.
Beyond that we spent some effort on correcting for the Doppler effect due to ships’ motion, various schemes for echo enhancement. You have to discriminate between the echo and reverberation, and so you use all of the processing schemes that we could think of then for enhancing this; and some of them we had in the form of packages that could be put on the gear. Early in the war, we went to work on the concept of scanning SONAR so that one of the major accomplishments of the Underwater Sound Laboratory was to bring forth and nurse and develop the concept of scanning SONAR. I don’t know whether you can say it just barely did or didn’t make the war—actually one of the experimental vessels at New London with one of our scanning sonars was one of about 30 vessels that pursued the last German submarine that was sunk off Cape Cod, and this poor submarine was sighted and attached—everybody converged and there must have been 40 attacks on this one; and everybody thought that they were the ones that got it. So that our scanning Sonar was in one engagement, but almost as soon as the war was over—let me say, almost no post-War sonar equipment has been built that does not use our scanning sonar. And it eventually turned out that about half of our program was on the Acoustic Homing Torpedo.
This was a major undertaking and a major success, a prime accomplishment, I think. The acoustic homing torpedo is a fascinating story. It’s fascinating from several viewpoints. It was the first homing weapon—the first guided missile was the acoustic torpedo. There was one Azon, azimuth only, bomb thing that was a gliding bomb that could be steered a little bit in the horizontal that was used in Southeast Asia a little earlier than this. But as a guided missile, this was the first one. It was top secret. And in general the life of a “secret Weapon” is estimated to be about six months. But the people that give those estimates don’t think about the special characteristics of naval torpedoes. Except in rare cases, such as when the Japs let one scoot up on the beach, if the torpedo is not successful, it sinks, but it isn’t found by the enemy. So that this weapon—it was less than 18 months from proposal to service use—it was estimated that at least 12,000 people, including the sailors on the ships that handled it, came in contact with it by the summer of 1943: at the close of the war in ‘45 when they examined the records, there was no indication that the Germans ever knew we had it.
Beranek:Is there indication it was a success?
Hunt:Oh, yes. Yes. Very successful.
Beranek:Tell us anything you can on this.
Hunt:I didn’t review the numbers on this but in the closing-up stages of the Underwater Sound Lab I tried to do some statistics on this. And it turned out, I think, that if you said that we had a 40% share in this and the Bell Labs had 60% or even if you divided it 30 - 70, I think it worked out to something like a 60th of a submarine or a 16th of a submarine, I don’t remember which, per capita in the laboratory and that we could have undertaken to sink submarines at so many dollars apiece and have paid for operation of the laboratory.
Beranek:How many submarines did you get?
Hunt:I think it was somewhere between 30 and 50.
Hunt:This went into operation in May/June ‘43. It was within a month of the same time that ten-centimeter radar was first put into operation in the Bay of Biscay, the British airplanes flying surveillance in the Bay of Biscay. Now the 10-centimeter radar is always given credit with having broken the back of the submarine war because the German intercept receivers wouldn’t receive the 10-cm stuff so they didn’t get the word to submerge—so the l0-cm radars caught them on the surface and the British played hobs with the ones that were coming out of the Bay of Biscay. What they never kept any score on was the number that the carrier airplanes had gotten by dropping the Mark 24 mine on them. But this went into service at the same time that the radar did and the two of them did, indeed they list this on the war statistics, this is where the submarine war turned the corner.
Beranek:Wasn’t there a third factor of knowing where to look through the operations research? Didn’t that start to be effective about then also?
Hunt:This, I think, was more specialized and local. One of the boys that we recruited from Phil was John Tulham, came to us—then Phil took him back for the Operations Research. Tulham scored two remarkable beats with this: one, he figured out how to lay down a barrier patrol across the Straits of Gibraltar—they did this and caught at least one submarine with it and they did an analysis in the Pacific that allowed them to change their scheme and become much more effective. I think that this didn’t influence the battle of the Atlantic so much, at least, not at that point. I learned a lot of lessons, of course, during this episode—one of the first and hardest to learn: I’d been playing with instrumentation and I thought I was a clever electronicer, you know, and if given a problem, I could solve it—and what I had to learn, had to accept (and accepting It was hard) was that in setting up, organizing projects for the Laboratory to do, I couldn’t promise the kind of performance that I thought I could accomplish, or would have done—but I had to promise what the gang could deliver, and you feel that at any one of these jobs, you would have beaten the guy at it. But you can’t sell that because you can’t be everyplace, you have to sell what that group can do. And this is a hard pill to swallow.
Weiner:How can you estimate that? You can’t just invoke a team factor of something and then reduce the expected results by that much.
Hunt:Oh, you overextend them and you commit them, and then they do it; and you learn that next time, you don’t promise quite so much and so on.
Weiner:Just a question of experience.
Hunt:That’s right, you have to feel your people. You have to ask them. It’s a feedback proposition.
Beranek:Now I might throw in a point here to see how you react to it. I remember that at one point in the operation of your lab, one of your associate directors spoke to me, and he was grumbling that Ted used to go around to the men individually and would sort of countermand the orders that the Group director would give them by seeing a better way to do it, thereby upsetting what was going on. Did this ever really happen? Or was that his idea?
Hunt:Oh, sure, it did. I got in lots of trouble that way. As the Director, as an administrator, I knew more technically about what the projects were about than any other laboratory administrator that I knew. And this was the way I had to operate. And so indeed I did know what the boys were doing. We worked out some very fine intercommunication schemes: we had this weekly; it was called the Progress Report. One gal spent her time going around to each of the men one by one once a week, and say what have you been doing this week since I was here last? And you didn’t allow the man to take the time to write it down himself—that would take too much time—he had to tell her; and she’d take it down in shorthand; then she’d go back and put it into English and get it out once a week; and you read it, so you know what Allen is doing on the bench down there. And if you see he’s doing something, he’s having this trouble and if you’ve got an idea, you could go in and look over Allen’s shoulder and say, look, why don’t you do this? And, yes, sure you get into some trouble by sticking your nose in other people’s business. But I get my nose banged that way a few times, and so you learn to be more careful about it. You learn to go through your own channels. Yes, we had lots of internal frictions. The boys tried to kick me upstairs one time and persuade me that I ought to concentrate my attention on higher policy matters—let them run the laboratory, you know, Get out!
Beranek:This happens to all administrators.
Hunt:There were two crises of that kind that I remember: one was an internal one with the next echelon of staff that tried to kick me upstairs; there was another one with the business office—Bill Claflin, William H. Claflin, who was then treasurer of Harvard...
Hunt:In Conant’s absence, he was the sort of acting Yes-and-No man. He didn’t try to do the things the president does, but he was the Yes-and-No man. And he was the one who had backed me—I mean it was, in other words, I felt that I was serving because he said that was all right. And on these two occasions, the business office was making reports directly to him, not through my office. So I had to lay it on the line: Is the business manager working for you, or is he working for me?
Beranek:Did you have much contact with Henry Wood?
Hunt:Yes, a good bit, in that he was the leg man for Bill Claflin.
Beranek:And then the other fellows name was Crocker, was it?
Hunt:Yes, there was a Crocker. But on the two occasions when I went to Claflin and laid it on the line, he backed me and said, “You’re the director, he’s working for you.” So this came out all right.
Beranek:Now I was always very pleased that the school recognized you through the honorary degree at the end of the war. That must have been a thrilling occasion in your lifetime.
Hunt:It was indeed. I learned how Harvard does these things. You get a letter around the middle of January, and Katherine called me up on the telephone and said, “Very exciting letter.” And I could hardly wait to get home. But you can’t tell anybody. You can’t tell anybody. This was high, top secret’
Beranek:That’s right. Right up to the minute.
Hunt:And remember there is one store at Harvard Square that I will still not deal with because I tried to get a suit of clothes for this occasion, and it was going to take so long—I said for a special reason I have to have it by such and such. No, just the regular time; I couldn’t tell them what the reason was. And—yes, this was very exciting. And as I said last time, it had overtones of basis for satisfaction. And, of course, in much the same way, the Medal for Merit—I always have a feeling that there’s some politics around; I don’t think these are bestowed quite uniformly on the basis of merit alone—but several people in the Division Six got them. I remember Colpitz; I think he got his at the same time I did, and…
Beranek:Didn’t Tate get one?
Hunt:Tate got one. And this, of course, was very gratifying.
Beranek:Was yours presented at this banquet that I went to in Washington—or was it someone else—I can’t remember now. There was a banquet at which a Medal of Merit was given, and I can’t remember whether it was you or another person that got it—or two of you that night.
Hunt:There were four of us at the time I got mine. And it was a banquet, but I don’t remember whether that was the one or not.
Beranek:I think I was invited there. Probably because I was a student of yours—I don’t remember.
Hunt:Well, we were speaking earlier about the question of personal research versus stimulated research. You remember that during the war with the N.D.R.C. projects, there was the designation, Principal Investigator.
Hunt:The head man on the project was the Principal Investigator. I always had a feeling this should be in quotation marks. Someone said one time, “You ought to be called the Research Instigator, rather than the Research Investigator.” And I always took kindly to that remark, because I have a feeling that this has been my chief role—what you call the Idea Man, rather than the executer. And when I was in the process of making this list up today, I said to my wife: “Gee, most of the things I’ve done were done by somebody else.” On the scanning sonar, for instance, I have a strong feeling of authorship of that yet my name isn’t on any of the patents, I think. I was always pushing somebody; Why don’t you try this, Why don’t you do that—and then he does it, and it’s his idea. Fine. But we got a scanning sonar. Then it’s more or less true of the things that wound up paying off on the torpedo and the B.D.I. And you go down the line, a lot of these phonograph jobs—Demy Lewis did the definitive mathematics on tracing distortion, but he did it because I pushed him and needled him and told him which part of the problem was the important one to work on—and when to quit. Same with Miller and Walkling and so on.
Beranek:There’s another thing, too, in your life that ought to be mentioned on the record. And that is that you always have written clearly, you write well.
Hunt:I speak lousy, but I write clear. Well, I use different standards. Speech is for communication—writing is for the record. And I take writing seriously, and I care whether what I think is crucial is right or not. So many people say: Well, that’s all right, they’ll understand it. And this is the lame excuse for bad writing I think. And, yes, I’m afraid I’m getting a reputation for being a hard man to write a thesis for on this score. But I’m always gratified when a few of them say: Gee, I’m glad you made me do that—I certainly feel differently about that now.
Beranek:Well, I remember when we’d write a paper—and I did write one jointly, as you know, with you and Maa. You used to put a music stand up in front of your chair and place the paper open on the stand and then flip the pages over as you would pages of music and would edit as you went. And we used to sit and you would read out loud as you edited and have us sit around and be critics: Did we understand this, should we say it differently, and so on. We had a kind of little symphony of writing.
Weiner:We’re taking a short break to use the other track of the tape.
Beranek:Maybe we could continue on the subject of science, Ted.
Hunt:We closed up the Underwater Sound Laboratory about the Spring of ‘45. I think, as I hear now people talk, other people knew the submarine war was over before we did, in a sense. And in retrospect, I think this may have been because we had our standing sonar development coming along so well, that it seemed a shame to stop this as long as you had any more submarines to attack. And Japan still did have. So we kept on pushing. But the sonar half of the laboratory was transferred to New London in May-June, 1945, and Dr. John M. Ide, then of the Naval Research Laboratory, came up to New London to, in effect, act as the receiving host by way of the New London Laboratory being transferred from Columbia University to the Naval Research Laboratory. And since this was to continue as a civil service laboratory they then, as now, had some difficulty in recruiting so that they did not get all of our sonar crew. But they got all of our equipment and some of the men. The ordnance half of the laboratory—the torpedo half—went to Penn State University in what could be described as a three corner deal. Penn State wanted Walker to come and be head of their electrical engineering department. The navy wanted Walker to keep on doing something with torpedoes and Walker was interested in promoting some more work and so Walker would go to Penn State if the navy would put a laboratory at Penn State to do the torpedo work—the navy would put the laboratory at Penn State if Walker was there, and Penn State was willing, so Walker established the Ordnance Research Laboratory at Penn State with the support of the navy’s Bureau of Ordnance. And the morale was higher in the torpedo division than it was at that point in the sonar division. And this was a University and not civil service, so Walker not only took almost all of the torpedo people but also a substantial fraction of the sonar people. In the meantime all the equipment left Harvard and—
Beranek:And I hired the remainder of your sonar people.
Hunt:You hired the remainder of the sonar people to do systems research at Jamestown, Rhode Island. And I came back to Harvard to inherit your airborne sound equipment to go back to teaching school. We have rattled around together for a long time.
Weiner:This was a business venture in Jamestown, Rhode Island?
Beranek:Oh, no, I was director of two laboratories during the course of the war, first the Electroacoustic laboratory which we have already spoken about having started about the time that I got my thesis, and the other was—
Hunt:We didn’t mention the fact that the name of your airborne sound project to absorb sound and quiet airplanes became the Electroacoustic laboratory.
Beranek:As time went on. We started off just calling it research on sound control.
Hunt:The Electroacoustic laboratory and Professor Stevens half on psycho-acoustics was the Psychoacoustics laboratory.
Beranek:That’s right. And then as the war went on and the Kamikaze threat got big, I was brought into setting up one of the first systems laboratories in the United States to try and combat the Kamikaze effort and that was called the Systems Research Laboratory. It was operated out of Harvard but our research laboratory was down at Jamestown, Rhode Island, where we had space to have both boats and attacks by airplanes— simulated attacks by airplanes—in our laboratory.
Hunt:I might mention one thing about the closing up of Underwater Sound Lab, two things in fact. One, some of the people tried to escape—some did escape—before they helped us write the final reports. So that the problem of getting out the final reports was a burden that fell increasingly heavily on the residual of the faithful. As a consequence, the faithful who stuck around to finish the job in my own estimation rank pretty high. And those were the real characters and there were blessedly a good many of them. The final report itself constitutes an inch and a quarter thick printed, volume which I had to write. And this was a tour de force in a sense because it is the most nearly printable first draft I have ever dictated. I dictated the whole thing without notes. Because I was so full of the details about the project—sure—I knew what the projects were and so I told a story leaving the numbers blank to be filled in and this report took less editing than anything I’ve ever written I think. And, of course, it was classified. So that it has never appeared—it can now because along with the blanket NDRC classification it is now open. And we gave this the title “Applied Acoustics in Sub-Surface Warfare” and—in effect—this is my first book, which couldn’t stand on the bibliography as a book for a long time because it was classified.
Weiner:Is it now available?
Hunt:Not available, but it’s declassified. It is not available because there’re not many copies.
Weiner:In other words, it has archival value.
Hunt:It has archival value and we’ve got one in the library now.
Weiner:Do you have extra copies?
Hunt:I’m sorry you asked that. I have a couple.
Beranek:He would like it for the—
Weiner:The history of physics archives along with this beautiful supplementary documentation now.
Hunt:I’m not sure whether I have one for that purpose or whether you’ll have to wait until I die and you get the one in my own library.
Hunt:No. You don’t want to Xerox it. It’s too thick for that. But, at any rate, that was a book. Now, still in the underwater sound area and still things that I’ve done—that were done by somebody else—following the war there was the short-lived research and development board, RDB.
Beranek:That stayed through Truman’s Administration. That was then about six years after the War. Right?
Hunt:J. Stratton, now president of M.I.T., was chairman of the Committee on Electronics. And under electronics there was a sub-committee on acoustics, which Jay asked me to be chairman of.
Beranek:It was a panel on acoustics and you were the first chairman of that.
Hunt:I was the first chairman of that. One of the things this panel did in its review of what was going on in research was to start pounding the table, urging the navy to do more work at low frequencies in water.
Beranek:In terms of active detection.
Yes. To make the transition from the low ultrasonic range from the 20 to 30 kilocycle range down to the 5 to 10 kilocycle range, or even lower. And we thumped on this to relatively little avail. The Navy gave it lip service. The Undersea Warfare Committee was established in 1946 by, I think you could say, the tenth fleet and the Office of Research and Invention—ORI—the predecessor of ONR. They saw division 6 of NBRC—Harnwell was then the director of the laboratory in San Diego, and Shea, Tate, Colpitz—they saw these people escaping back to the academic halls, and they wanted to keep them together for the Navy. So, they executed a contract with the National Academy to set up this Committee on Undersea Warfare to keep this group together as an advisory group for the Navy. So I was a member of this committee from the start, and it is still thriving actively. It has, I think, made a reasonably distinguished record as an advisory committee.
It did such things as sponsor the Alba Corps, deep submergence, a number of things the navy has done that when they came out someone else had pushed, but two years earlier, we’d been pushing at them to do this. This Undersea Warfare Committee, for a time, held an annual symposium on undersea warfare, a classified meeting, to which, again, the purpose was to sustain the interest of scientists in universities and industry in the Navy’s problems in underwater sound. In the symposium held in the Spring of 1950 was the other one of these two papers I said were the most fun things I have had anything to do with. John Coleman, who was then executive secretary of the committee was arranging the program for this symposium, and he asked me if I would give a talk on long range detection. Sure. So, I started to work on preparing for this. And the more I worked on it, the more excited got. And what was intended to be a 15 or 20 minute paper turned out to be a 50 minute paper with about 25 minutes worth of discussion. And in this paper, I, in the most effective way I could, laid it on the line that the wavy ought to get off the dime and start being smart about using the underwater hemisphere for communication and detection. In the refraction problem there are lots of analogs in the ionosphere picture, in fact I used some of Jack Pierce’s ionosphere slides and turned them upside down to talk about what you could do in the ocean. I remember the last line of this was that you might have to wait 60 minutes for an echo, but the sweep rate was an ocean an hour.
Beranek:An ocean an hour.
Hunt:And, in this I had some wild suggestions about how to make cheap directive hydrophones, and how to use magnetic tape for correlation processing—
Beranek:And cheap low frequency sound sources—
Hunt:Cheap low frequency sound sources.
Beranek:It was a very famous paper. I was not in the meeting, but the repercussions of this were tremendous.
Hunt:Well, I think the reaction to this was only comparable to the way we upset the phonograph industry in 1938, because this was timely. And again I think it helped—triggering off the Harwell project and the old launching of long-range passage detection systems, it was the basis for what eventually turned into Artemis and it fed the fuel to the fire of working on correlation processing. So I think probably this was one of my most influential papers. It was never published in the open literature. I have got a manuscript and it’s not otherwise in print—but as you say I think it made a bit of a stir.
Beranek:This paper ought to be requested for your archives, I think, if we can get it.
Weiner:Well, only if it’s in the open literature.
It’s not in the open literature—so, that was that. Well, of course the work we do for ONR is not classified and I got into an interesting effort in one of the—we finally terminated the first ONR contract after ten years and started a fresh one. We’re still on the second one. I hope they don’t remember that it’s about time to terminate the second one and start a third time. But, the question of the difference between basic research and applied research. Then they got me to work this up for an article for the Journal of Underwater Acoustics for what called Motivated Basic Research.” And the story is with the undersea warfare committee activity continuing, I’ve been continuously in touch with the classified work of the Navy in underwater sound field. So that I know what some of the Navy’s problems are. Now I come home and talk to my graduate student about picking a problem. I can’t tell him about the Navy thing. This is classified. But I can describe a problem to him which has challenge, which if he can solve will be useful to the Navy. And if it’s a free choice—if you were trying to downgrade his effort from one thing to another, it would not be defensible.
But he has to choose among the things he does and he might as well choose one, the solution of which is in the range where it might possibly be of use. And this has guided a lot of our planning of what my students do. It guided for instance the work that Pritchard did on the design of directive arrays, the extension of this by Bob Hills; the work that I stimulated Faran and Hills to do on correlation techniques which got published and is one of our best seller reports because they collected some of the material that had been in scattered reports at M.I.T. and put it in common notation. And so this is the place you start. I found out this recently—I got in some statistics and that was the place I went back to find it. The work that John Bouyoucos has done on hydrodynamic sound sources. This had a lot of possible applications, one of which was that the Navy is one of the people who were interested in alternating fluid flow, alternations such as 500 to 1,000 times per second, otherwise called a sound wave. So this started out by asking Bouyoucos if he could blow a whistle under water and in fact Bouyoucos can say that his career started in pursuit of that question.
Beranek:And he did blow a whistle under water.
Hunt:He did blow a whistle under water and he went on to how you modulate a fluid flow more effectively than that with higher efficiency. He and I jointly hold some basic patents on hydraulic oscillators and he’s now at General Dynamics in Rochester, indeed making a career out of the exploitation of this underwater whistle. In a remotely related way I worked on cavitation. Cavitation ultimately turns out to limit the power you can put into the water for the transducer. So what do we know about cavitation—so you study it—and this is perhaps the prime example of the work I’ve done that was done by somebody else. There are now six people, four who have completed their work and two who are still engaged in it in the field of cavitation since Blake started about 1948. I’ve never published anything in the field and have a feeling that this is my field. So that in succession Blake, Rosenberg, Hugh Flynn, Jim Barger did theses in the field of cavitation, each building more or less on where the previous one left the subject. And Morgan is now pushing in one direction from where Barger left his thesis and we have a postdoctoral fellow in this year from Michigan State, Lester, who is pushing in another direction from where Barger left the subject. We worked on the subject of acoustic cavitation, usefully I think, so that we are probably one of the centers of study of acoustic cavitation in the world—but none of it is my personal research.
Weiner:Now you’re into that other important area, I think we mentioned, about the doctoral candidates.
Hunt:Yes, these are some of them and this is the “research instigation” area.
Beranek:Can you run through your forty doctoral candidates by name and present location, or do you need the list.
Hunt:Oh, Great Scott—yes, I would need the list.
Weiner:I would suggest that this is something we follow up and we ask for that—
Beranek:You can mail that.
Hunt:I have made it up and reviewed it recently. I did some statistics on this a few years ago and about sixty percent of them are still in acoustics or something related.
Weiner:Well, I think we can get that later.
Hunt:Let me skip a bit.
Weiner:Please go wherever you think it’s most fertile for us.
Hunt:What I was going through here were the researches instigated or otherwise related to underwater sound. The cavitation, as I say, is fairly remotely underwater sound although it is acoustic cavitation in water that has been wholly a student thesis job. I’ve been involved in electroacoustics, I guess you might say the phonograph pickup is a mechano-acoustical transducer. Then the work at the Underwater Sound Lab on magnetostriction transducers, pushed with Art Janszen, Art Janszen as an assistant did the leg work, the manual work, and we revived in the l950’s the electrostatic loudspeaker which had been put on the shelf in the l920’s as being not useful. With new materials and some new techniques and one or two new ideas we revived the electrostatic loudspeaker and my contribution to that was to work out the mathematics of the push pull version and to prove its unique virtues with respect to distortion. It is potentially the most distortion-free loudspeaker we have and so the analysis of why that should be so was mine. Then in the early 50s I finally made my peace with what I call my K factor for dealing with antireciprocity in equivalent circuits and put this into my momograph on electro acoustics which came out in 1954.
Beranek:Who was the publisher?
Hunt:That was originally Wiley-Harvard University Press in a joint imprint. The Press manufactured, Wiley distributed and this was a Harvard Applied Science Monograph Series of which I was the chairman of the Editorial Committee and this series has since bursted. Wiley pulled out, the Press took it over entirely, and to the best of my knowledge it has died now.
Weiner:What motivated you to write the book on electroacoustics and how long did it take on account of your other activities?
Hunt:That’s a good question. Having taught this course I had the usual teacher’s notion that I would write a text book for the course because we didn’t have one. We used reference books but there were no text books we could follow. And so I started in the period from ‘45 to early ‘50’s—I started to write the text book and in fact have in mimeograph form the first seven chapters. Then along in the middle of this Leo comes out and publishes a book stealing the thunder from my chapter on the wave equations pretty much.
Beranek:No, mine was an elementary wave equation, compared to yours—I didn’t even try the nonlinear case that you did.
Well no, but I didn’t do much—very much non linear either. And the good solid fundamental part Leo had already done. Chapter 8 of this was supposed to be electroacoustics and having most of the seven chapters I thought, well, let’s get on with this, I’d better start to work on Chapter 8. So I started to work on electroacoustics and pretty soon this began to get pretty out of hand, that is, it was getting to be much too much for a chapter. And since I had already been hooked to be chairman of this editorial committee for the monograph series, I said, well, maybe we can make a monograph out of it. And then there was a problem because I hadn’t finished—we had some of the work on magnetostriction but not on the crystals—but to do magnetostriction and piezo electric transducers would have delayed it some more.
So we took refuge in the fact that the title is Electroacoustics and everything that’s in the book is electroacoustics. It doesn’t claim that it is all of electroacoustics so this is electroacoustics of lumped systems and it contained the unified homogenous treatment of magnetic and electrostatic coupling, using my new K factor, so I got this published and the electrostatic stuff. Well, in a text book it would seem to me sort of natural that if you had a chapter on horns you ought to introduce it with a brief paragraph on the history of horns. And when you come to transducers you ought to have a brief introduction on history. Well, that I’d encountered some time earlier and I’m not sure—I guess it was before—I started saying, well, maybe I ought to collect the history and put a historical chapter at the beginning and then get into the mathematics. So I started to write the historical chapter. Well, like the electroacoustics this got out of hand and you start following footnotes and it’s like eating peanuts, you can’t stop, one footnote leads to another. So I wound up with a manuscript on the history of acoustics. I called it the Origins of Acoustics because there were as much origins of other sciences in acoustics as there were acoustics in other sciences and so you’re looking for origins. I still think this was a nice title for it, not that anything will ever come of it. So I had this up to about Newton I guess and so when the...
Hunt:Well, to my great surprise, I found out that there was a whale of a lot more in the ancient times and the so-called Dark Ages were only dark in Western Europe, they weren’t at all dark in the other places. We’re talking about sound, nobody much—there weren’t many physicists writing about sound but everybody wrote about music, and everybody that wrote on music had a chapter on the production of tone. So that you find that the history of what is known about the science of sound in the production of tone sections of the treatises on music and this is lush all through the so-called Dark Ages, the Medieval time and the Renaissance, the material up to Newton is a substantial bite.
Weiner:About how many typed pages is there in its present form?
Hunt:Oh, something like three hundred. It’s almost a book. Having cut my teeth on original references—I decided if you’re going to do this you don’t pay attention to what other people write as histories you go back to the sources—so I didn’t cut my teeth on that. When I came to doing the historical introduction to electroacoustics this, all by itself, almost got out of hand. It winds up that about forty percent of the monograph on electroacoustics is an 110-page history of electroacoustics and this turned out to be lots of fun but it took a lot of time.
Weiner:You know, I’d say it’s the only existing history of the subject, as far as I know.
Hunt:Yes, of electroacoustics, that’s right. The early electricity is very well documented and that’s where some of it comes from but again you have to read it in the acoustics context.
Beranek:I was asked to present a paper at the twentieth anniversary of the Acoustical Society on the history of electroacoustics. After I had gotten along on this I learned that Ted almost had a book coming out on it. So that I, in defeat, knowing that this was going to be quite a deal—in fact he showed me the galley proofs on it—went out and collected a few old pictures and said I was presenting some of the illustrations to his book.
Hunt:I’ve got those slides down on my rack. I noticed them just the other day. Well, that came out in ‘54 I guess and shortly after that—well, during the time I was working on this history, some students were working away and there was sort of a backlog of stuff built up so that ‘55-‘56 I had to go back to clean up the accumulation of papers and there was one period of about a year when I did about five or six papers on a rather odd assortment of subjects. At least it seemed to me at the time slightly odd.
Weiner:“Lantern Slides Without Photography.”
Yes, and then “Elastic-Plastic Instability Caused by the Size Effect and Its Influence on Rubbing Wear,” and, “A Wide-Range Logarithmic Volt-meter”—well, then I was sucked in, I think is the word, to write this section for the American Institute of Physics handbook on the propagation of sound in fluids. I had told Firestone there ought to be such a section, so as usual, it winds up with “Okay, you write it.” And found out that if I was going to write this in tension notation, the way it ought to be, you really had to do it right, but what I hoped would be a three or four week job turned out to be a six-month job, which was very educational, “Stress and Strain Limits on the Attainable Velocity in Mechanical Vibration,” “Physical Principles Underlying Contemporary Sonics,” “Notes on the Exact Equations,” the voltmeter and the elastic-plastic instability, and the lantern slides without photography. That was one of these flyers. I was about to give a paper and I hadn’t had time to make slides, so I got some brown glass and wrote on it with pencil, and this you could project and it showed, but the contrast is not very good, It occurred to me that if you put a drop of water on this, that as long as it stays wet, it’s nice and transparent. The brown glass gets transparent.
The question is why can’t you put a plastic layer on and preserve the transparency, and ungrind the glass. And the answer is, yes, you can. So I showed some slides at Penn State—I went out and bought some collodion, and this got kind of messy around the edges, but you could flow up some collodion, and essentially, this is what Polaroid uses for their film coater. A thin plastic is self-leveling and will fill in all the hills and valleys in the ground glass, and if the refractive index is all right, you restore the transparency, you ungrind the glass. So you write on it and then cover it. So this was fine, and I applied for a patent on it, and got a nice patent on it—and by the time the patent came out, Polaroid announces their transparencies in the back of the camera, you know, in 50 seconds, and the little plastic holder, and you can’t beat that. So that, again, is one of the—the patent things that won’t pay off, I’ve got another one now. I’ve got an improvement on lighter flints.
Weiner:How did you come to that?
Hunt:Well, the flints—
Beranek:—they wear out—
Hunt:It doesn’t work very well, and you look at it—most of the surface that you’re abrading with the sharp wheel and the little particles that you pull off are hot, get wiped across the cold surface of the flint. Well, the only part that pays off is the edge that’s closest to the wick. So, how do you increase the length of edge that is facing the wick? The answer is, you groove the round flint. And if you make it a star form, there’s a maximum shape that’ll produce the maximum surface.
Weiner:What started you, though, on a problem of that sort?
Hunt:I had trouble making the lighter work sometimes. So I figured maybe you could do this, so I challenged one of the boys in the shop to grind spiral slots on a lighter flint, and darned if he didn’t do it. So I tried them and it works fine. Whether I could ever sell it to anybody, I don’t know.
Beranek:I have two more questions.
Hunt:I think I’m almost through with this thing. We got in the history.
Beranek:I have two more questions. The first one has to do with postwar activity you were in. I guess you entered into this about the summer or late spring of 1946. The newspaper said that Dr. Hunt is on the academic prowl in quest of replacements for a lost generation of engineers and scientists diverted from postwar labors by wartime manpower requirements. Industry needs research engineers well-grounded in basic sciences. It will be Dr. Hunt’s job to help train and supply them. And this led to your being chairman of a new department at Harvard called Engineering Sciences and Applied Physics, or ESAP as you call it.
Yes. This is a sad story, I think. I suppose you could say it’s a sad story with a happy ending. I mentioned the fact that Cruft’s laboratory was midway between the Physics Department and the Graduate School of Engineering. The Graduate School of Engineering contained Civil Engineering, Soil Mechanics, Sanitary Engineering, a lot of plain garden-variety honest-to-God engineering. During the war Conant, like a lot of other people, had seen physicists turned into engineers, and had seen how effectively they made the transition in such things as went on at the Radiation Laboratory. So that Conant came back from the war, as it were, fairly disenchanted with what you might call old-fashioned engineering. His first move in this direction was to propose, as a sort of trial balloon, to stop offering Civil Engineering in the Graduate School of Engineering. He wanted to cut this out, and to form a new section, division, or something, to train scientific engineers. Well, the first proposal of this, I don’t think I’m making a very good description of what he proposed, but among other things, he was going to abandon Civil Engineering. And the reaction, as could be imagined, was pretty violent and vigorous, and I think this is partly what Conant wanted to stimulate.
So, there were a couple of meetings—these were special meetings, not regular faculty meetings, but meetings of a special segment of the faculty to which he announced this plan, and another one to discuss it. And then Professor Fair made a compromise suggestion that, in effect, suggested that a new department be set up to do this, and anybody from the engineering school who wanted to join this could, and the presumption was that the staff of the Cruft laboratory would be the nucleus for this. Cruft was already in this position of training scientific engineers for the communication engineering, so some could join it, on sort of a voluntary basis. This is the way it finally came out, and Dean Buck, who was Provost, and who, as Provost in Conant’s absence had had some contact and seen me at work, in effect, put the finger on me to act as chairman of this group. Well, I’d seen the conversion of these scientists into engineers, but I’d had my nose rubbed in the fact that you can make good engineers out of scientists, but it’s hard to make a scientist out of an engineer—engineer meaning basic training this way. So that I was sympathetic to the idea, and having spent the previous four years in more or less the administration, I was ready to take sort of a deep breath and say, well, instead of going back to research, maybe I should get up and campaign for this, because it’s something that I believed in. I’m a good salesman if I believe in something. I can’t sell anything I don’t believe in. This was why I was a good recruiter—because I believed very deeply in what I was trying to sell. Well, in brief, the plan aborted. Only a few—two or three of the people from the Graduate School of Engineering elected to join the new group.
Hunt:Faculty people. And, as chairman of this group, we were almost sub-critical in size. The Engineering School was still operating, so that we were not the replacement for it, we were an extra. So that the competition remained. And this was, what you might call unstable. If all of the people in the group had been of one mind, we might have generated enough internal enthusiasm to have made more noise and carried it. But, we were not of one mind. Professor King, Professor Nimno, had not been in the war laboratories, they came to these problems with a different point of view, and this was the point at which the difference between department chairman and department head made a big difference.
Beranek:You couldn’t tell them—
You couldn’t tell them, and as chairman I spent all my time arguing with people, trying to get a consensus among our own group, and not very successfully. The computation laboratory—Professor Aiken was not an easy person to work with, which is one of the grossest understatements I’ve made today, and though I was psychologically ready to have devoted myself to the promotion of this concept of engineering education, which I still believe is sound was the thing, and Harvard had a wonderful opportunity to have been the leader in this, because no one else had started down this track yet—but the internal dissension between this new group and the Engineering School, of course, did not sit well with Conant. That is to say, he wasn’t bothered by it, but it wasn’t a thing which enlisted his enthusiastic support. And whenever there was a showdown in which we were really in conflict with the Graduate School of Engineering, Conant did not back us, did not back me as chairman.
Moreover, at no time in the three years I served as chairman, did Conant ever call me into his office to say: What do you think we ought to do? I had the feeling that I’d been put up here and got no substantial backing from the administration? I was ready to go around, make speeches, and say this is the way to educate engineers, but I couldn’t do this when I couldn’t say that we had agreement among our own group. So that after bucking this for three years, I decided that this was a bad game and, let’s see, I guess I started in—Buck had asked me to do this in January, so that I’d counted from the first of February ‘46, and appointment of chairmen were from three to five years. So I invoked the minimum limit and asked to be relieved of this in February ‘49, and Buck asked Professor Chaffee to step in and, take it over, which he did. And so, in February of ‘49 I had my first sabbatical. It was not really a sabbatical but that was when I went to Cuba for two weeks. I got out of this job, and there were I think three subsequent reorganizations and change of name.
Hunt:Well, yes, I think so. Maybe it was three in all, and the present status is the fourth. I don’t know—I’d have to draw a diagram to make sure of that. And the present situation, I think, there’s been one name change since 1952, but it’s been stable now for about 10 or 12 years, and I think is a viable unit now.
Weiner:What’s the present name?
Hunt:Engineering and Applied Physics.
Weiner:And—the original was Engineering Sciences and Applied Physics.
Hunt:Yes. But in the meantime the Graduate School of Engineering was dissolved and became a Department of Engineering in the Faculty of Arts and Sciences. Then it was merged into a single department. Then there was a name change. Or then it was merged into a Division. Then there was a name change.
Beranek:Now what is this thing now? Is this a department?
Hunt:It’s a division of the Faculty of Arts and Sciences. And it is a division because of two reasons. It embraces many subjects, such as the division of biophysical sciences, and secondly, divisions have deans, not chairmen, and it has a dean because it has a budget, it has an endowment. In other words, Harvey Brooks is the Dean of the Gordon McKay Endowment or the dean of the Division of Engineering and Applied Physics. It is a division because it embraces everything from Soil Mechanics and Sanitary Engineering to Solid State Physics.
Beranek:Now, is your appointment in this division now?
Beranek:And what are your titles nowadays?
Hunt:Let’s see, when we formed ESAP, the Cruft people became professors of applied physics, and the engineering people became professors of engineering science. Now they’re professors of engineering. So you’re either a professor of engineering, of applied mathematics or applied physics. All professorships supported under the Gordon McKay endowment must carry the name Gordon McKay. So, automatically, in 1946, I was a Gordon McKay professor of applied physics, because I was paid under the Gordon McKay endowment. Professor Pierce had been the Rumford professor. When he retired, Professor Chaffee was made the Rumford professor, and when Chaffee retired, which was ‘53, I became the Rumford professor of Physics. So I am the Rumford professor of Physics and the Gordon McKay professor of Applied Physics.
Beranek:Does a Rumford professorship have much money in it, or is that mostly an honorary title? This, of course, wouldn’t affect your salary, I know…
Hunt:That’s right. It doesn’t. All it does is take a little bit of burden off the Gordon McKay endowment. At the time I took over, I think the income from the Rumford was something like $2,900 a year. Now, I haven’t looked this up, but sometime back, Harvard made some rearrangements of their endowments, and they beefed up all of the named endowments so that they had enough capital to carry them. And whether the Rumford professorship—that is, whether I am wholly paid by a beefed-up Rumford fund, I don’t know. But, the Rumford professor of Physics had been sort of an applied appointment in the Department of Physics, at least it was in John Trowbridge’s time. And, at the moment, I am a Rumford professor of Physics, but I am not a member of the Physics Department.
Weiner:It is interesting to note here that in 1846, the Rumford professorship was offered to Joseph Henry, and they were trying to increase the salary in order to attract him to about $2,500 a year for a total salary.
Beranek:Ted, I don’t know if this is classified information or not, but what does a professor at Harvard hope to earn nowadays—a full professor who’s been around for a reasonable length of time.
Hunt:I have to stop and think—I think I got a raise last July to $18,000.
Beranek:It used to be $12,000 when I was here.
Hunt:Yes. It’s inched up, and occasionally, the President, in his report to the faculty every year, sometimes gives a figure for the average salary of a professor. Whatever that’s been, I’ve either been just under that or just at it. So that, my old record of being in the trailing edge of the phase curve is holding. I think the regular professorships range from $15,000 or $16,000 now to $22,000, but in that range. Maybe the minimum is $14,000 now. But it’s been raised from $12,000, and at one point the top was $20,000, and I think it may have been raised also. Then the University professorships are the ones that are the plums.
Beranek:The final question now is one think you might enjoy. I’m quite sure, from being with you for a long time, that you have enjoyed the Acoustical Society of America, and in fact would suspect that it has been one of the focal points of fun and places to report and so on. There have been some mighty interesting people in it, like uncle Harvey. Maybe you’d like to comment on the Acoustical Society of America.
Hunt:The first meeting I attended, I think I said last time was in 1931 at Camden, RCA, which was the fifth meeting, and to the best of my knowledge I haven’t missed a meeting since then. I don’t know of anybody who has a better record of attendance, including Wallace…
Hunt:Well, except that Wallace covered the first—of course, he founded the Society practically, at least he was present when it was born. Well, he has the first four meetings on me. But since the fifth, I think he missed one that I didn’t. So you’re quite right, I’ve felt that this is my Society, and as a youngster, the Society was a youngster, too, so that, in no society that I know of, in the 1930s for example, could one join the Society, go to the meetings, and in such a short time, be able to call 50 percent of the people present by name, Now, I’ve lost ground on that fraction a lot since then, but it still preserves a feeling of intimacy that I don’t think is matched in any other Society that I know of. As I was asking you before we started our session today, the Society has now appointed a so-called “high level” committee of ex-presidents to review the organization and function and purposes of the Society to recommend whether there should be any changes in them. This is partly precipitated by Wallace’s incipient retirement. Should there be any changes in the organization, the Secretary’s office, and so on, and...
Beranek:Is Wallace again considering retirement as Secretary?
Hunt:Well, not for at least three or four years. But at least it’s early enough to have stimulated somebody to think—I don’t know if someone has a beef that I haven’t heard about yet, but the committee at least is specifically asked to consider this question, that should there be centralized billing, and should there be any change in the office of the Secretary in the organization of it? Should the next Secretary also be lodged in the Institute, and so on? And so this is the forward look on whether the Society should change any. It’s a good group.
Weiner:How would you characterize its development over the 30 years that you’ve been involved with it, in terms of your own participation and—other than the good will and good feeling that you’ve gotten from it in the sense that this is your professional peer group—what about your role in the Society and your view of the Society’s function? And then some brief comment on what changes you’ve observed in its internal and external growth.
Hunt:Well, I think the changes that one observes is merely that it’s gotten bigger, but not as much bigger as I think it should have gotten.
Beranek:It hasn’t grown really.
Hunt:It hasn’t grown. The Society has had a curious reluctance to recruit. And I think an over reluctance. We go to meetings of these Underwater Sound Symposia. You go to meetings of the IRE—ex IRE—now IEEE, meetings on ultrasonics, professional group on audio—they’re both comparable in size to the Acoustical Society. The Audioengineering Society is 2/3 of the size of the Acoustical Society, and many, at least half and probably 2/3 of the people in those other groups, ought to belong to the Acoustical Society, in terms of the objectives and functions of the Society. Yet, you sometimes ask for a show of hands, and get a disappointingly small fraction. But I think there’s a lot of places to recruit effectively—of course, the Society’s journal is a bargain, one of the best bargains going, in the number of pages per dollar and quality of the material. The answer is the Society has grown, but not as fast as the number of professional people who are interested in acoustics in the large sense, including its applications. I don’t know whether it’s a group of displaced physicists or a group of engineers, or a group of psycho-acousticers. But I think, personally, that it’s a mighty fine idea to keep this decision uncertain.
Weiner:Can I suggest what I have heard people comment on a central theme running through the history of the Society, and that is the concern with standards? In fact, the very birth of the Society came about because of the need to define uniform methods of acoustical measurements, particularly as applied to materials.
Hunt:Yes. I was going to say, that’s a very special problem, and that wasn’t so much a problem with standards, as it was a problem in knowing what to measure.
Weiner:We started out with that earlier today as the current problem of acoustics.
Hunt:We used to call it the battle of the coefficients. And I think, from our point of view, this battle was terminated with our paper on rectangular rooms.
Beranek:I think so.
Hunt:This was the story on the absorption of materials. Some of the questions that we fought over in the early 1930s, people are still arguing about. They still don’t understand. But this was an uncertainty and an interest in a problem of measurement, rather than a problem of standardization. It is true that the Acoustical Society has, I think, shown a lively conscience about the matter of standards, more so, for instance, than the American Physical Society, which couldn’t care less about standards, by and large. That’s for somebody else to worry about, or the manufacturers. And the Acoustical Society has, I think, shown a lively conscience about nourishing good standards, and they’ve also, largely through Larry Batchelder, have extended this into an international conscience—conscience about international standards. This is useful, I think. It’s a useful activity. But, it’s one that only a small fraction of the population can get very excited about.
Weiner:This leads me to three sub-final questions that perhaps can be answered in one paragraph. And that is, what do you think are the major problems facing researchers in acoustics, and, I would define it this way, major problem concerning acoustics as a professional field of inquiry; whether this be an attraction of people to the field, whether it be public understanding of what is involved in acoustics and effects on public life? We have seen acoustics in the newspapers recently, with different editorials and so forth, and it seems to be more in the public eye now with sonic booms, too.
Hunt:Remember, the Ford is quieter than a Rolls Royce, according to these experts.
Weiner:These are some of the questions that I think that raise the question of acoustics in the public eye. What do you think—keeping the internal problems, the question of knowing what to measure, in mind—what do you see as the major tasks that have to be tackled? Then how you measure your own contributions to the field and can you perhaps, after all of this discussion, single out what you consider might be the central theme or at least one of the most important things that you’ve done?
Hunt:That question of the most important thing you’ve done is one that I’ve thought about and, I don’t really know the answer to that, but expect the most important thing I’ve done is to propagate 30 or 40 Ph.D.’s into the field. As I say, the most important things I’ve done, somebody else did, and thank God they’re still doing it, and if the laws of genetics work, maybe we can keep this chain going. That is not an attempt really to evade the question. I think it’s probably true.
Beranek:Can you name your most important research paper as a separate kind of question, in your own opinion, that is? You sort of told us this.
Weiner:There were two papers that he said were fun. Does that also mean that they were the most important?
Hunt:I’m not quite sure of that. I’m not sure of that for this reason. In its time, this paper on electronic stabilizers was an important paper.
Weiner:What paper was that?
Hunt:’38. Hickman and Hunt, Hunt and Hickman. But, you don’t do it that way anymore. You use operational amplifiers and zeno diodes. You point to some things that were important at the time, but the subject matter has changed, and this changes the importance. The phonograph business—it was important to point out these simple facts about the stylus groove contact, but everyone takes that for granted now; there’s no news in that.
Weiner:Because it was pointed out at one time—
Hunt:Maybe, but I suppose somebody else would have done it, but at least there’s no—this isn’t the Hunt effect. This isn’t like the Hall effect that continues to propagate and be a medium of expression of things from then on. And suppose that the most important thing really aside from the students is the influence that I’ve exerted on the evolution of underwater sound as a technique for gaining intelligence out of the ocean.
Beranek:And that came from this unpublished paper to some extent. I think that was a very valuable paper.
Hunt:Yes, but also the continuing things in the committee with ONR here—that is, as long as you can continue to have contact with Navy people, you can continue to urge and push and needle, and, I think influence to some extent the course of evolution of this technique—if there has been one single theme that I have sung it’s the fact that the Navy doesn’t exploit as effectively as it could the use of sound in getting what they want out of the ocean. You can do more with sound if you try—if you want to. This has been my theme song. And you keep on pushing at it, and I think that maybe over a period of study of the last twenty years or so that I have had some influence in this direction. I suspect that nobody can put their finger on any one thing in that area and say that Hunt did this, but this may be the most important thing, I’m not sure. The cavitation thing—this has been an important sequence of papers, but, again, we still haven’t got the answers and the man who gets some of the answers here will be the one who will be remembered in that field, not the spade work we did on the way. Now, what else did you ask?
Weiner:One question was about some of the tasks that you see facing acousticians of the future, and secondly relating it to the public’s attitude to the work that is being done in acoustics.
Well, acoustics as a field suffers now because it is deglamorized. I mentioned that in the 1930’s and for a period of about five years after the war students came to Harvard to study electronics, communications, and they didn’t quite know what was in these fields and so they shopped when they got here. Graduate students don’t do this any more. On their application blanks they say that they want to come to study lasers or gas lasers, or solid state physics, or “I want to do this.” A graduate student comes with much more sharply focused intentions. The classes that used to be fifteen to thirty, out of which you would salvage for further work in acoustics one or two, in the middle 1950’s dropped sharply down to three to five, and the class consisted only of the few people who came to Harvard to study acoustics. Now, the number of people who went on in acoustics to the second and third year did not diminish but showed a very slight gradual increase. While there was a change in the class population from an average of twenty or more to an average of not more than five. And this, I think, is the changing habits of graduate students, the changing offerings of our own division, in solid state physics, the glamour that is attached to solid state physics since the transistor, so that acoustics fights a rear guard action for good graduate students.
The hot mathematician wants to do theoretical physics and chase strange particles. By and large, acoustics is one of the last holdouts of classical physics. Now it is true that acoustics is getting to be more and more quantum mechanics in some of the interesting branches of acoustics, and some of the exciting stuff in acoustics now is on the quantum side, but the people who are doing this are mostly physicists who are dabbling with acoustics. They don’t come in because they learn acoustics and move in the other direction, so that you deal with a segment of the population that likes that kind of stuff. I don’t see any Nobel prizes in the field of acoustics partly because of the characterization of the subject.
I’m cribbing now from the introduction to my history book. In mechanics, in optics, in electricity, you can discuss the problems of these fields wholly in terms of the concepts of that field alone. Mechanical problems can be dealt with in terms of mechanical concepts, ditto electrical, ditto optical. But in acoustics you must always work with mechanics, elasticity, thermodynamics—and almost always with electricity (if you want to do an experiment). But you always have to merge these things.
In a sense, then, the problem of acoustics is to keep from committing suicide, because if you specialize in each of these fields, you fragment it so that there isn’t anything left for acoustics proper. It doesn’t have unique concepts of its own, and to try to give it some, which is what sometimes they do when they teach the subject at an undergraduate level, is artificial and phony. So I think it’s better to accept this as a straddle-field, as a merger-field. This is why the Nobel prizes will be in one of the components that make up acoustics, not in acoustics, but there are still a lot of problems to be solved.
Wallace Clement Sabine, Collected Papers on Acoustics, with a new introduction by Frederick V. Hunt (New York: Dover, 1964).
”Effect of Source Resistance on Electronic Stabilizer Performance,” Phy. Rev. 53, 913 (A) (1938); and “On Electronic Voltage Stabilizers,” Rev. Sci. Instru. 10, 6-21 (January 1939)
Session I | Session II