Listening for favorable concert hall conditions

Reverberation time (RT) quantifies the decay time of sound energy and provides a basic measure for the audible length of sound. It is an essential parameter in acoustics, as reverberation promotes the merging of individual voices into an overall sound and fills gaps between notes.

A target value for the RT is given to the architect as a specification when designing or renovating a concert hall. It is proportional to room volume and can significantly influence the hall layout, size, structure, and final cost. Defining this target value is therefore a critical first step in the design process.

While various values have been proposed for the preferable RT in the past, scientific evidence has been lacking. Hidaka and Nishihara systematically measured the favorable RT in famous concert halls with test signals from piano and violin solos.

“I believe that acoustic design of a concert hall is best achieved through a combination of artistic sensibilities of music and a scientific understanding of human hearing in a concert hall sound field,” said author Takayuki Hidaka. “Our knowledge of the latter is still insufficient.”

The signals were created by convoluting anechoic music — solos recorded in a chamber in which there were no reflections from the walls or the ceiling — with room impulse responses. The result was presented to 16 music experts for judging and comparison.

The favorable RT for piano and violin solos are 1.2 to 2.0 seconds and 1.8 to 2.4 seconds, respectively. Additionally, the clarity index is needed to satisfy certain criteria and should be accounted for in concert hall design.

The team plans to extend this work to study the preferable RT for orchestral music.

Source: “Favorable reverberation time in concert halls revisited for piano and violin solos,” by Takayuki Hidaka and Noriko Nishihara, The Journal of the Acoustical Society of America (2022). The article can be accessed at https://doi.org/10.1121/10.0009931 .