Investigating a glockenspiel’s vibrations

The glockenspiel, a percussion instrument similar to a xylophone, is commonly played in orchestras and ensembles. It is played with a wooden or plastic mallet that strikes the 30 to 34 metal bars affixed atop a shallow wooden sounding box. While the glockenspiel has been around since the 17^th century, little research has been conducted to understand how it radiates sound.

Most existing research has been conducted on the metal bars that make up the instrument, idealized as free beams, instead of integrated into the instrument. Pavill and Shepherd conducted an experiment with the glockenspiel in whole form to investigate how the bars radiate sound when played, which influence how the instrument sounds.

To first test the sound radiation, a glockenspiel was placed in an anechoic chamber. Different mounting configurations of the bars were tested. A scanning laser Doppler vibrometer was also used to measure the vibration of the bars, both when a part of the glockenspiel and when removed from the instrument.

“The most exciting part was seeing just how much mounting changes the sound,” Pavill said. “Small differences in how the bar is supported can lead to big differences in both the vibration modes and the sound radiated into the room.”

The results help show how the bar vibrates and radiates sound under normal playing conditions for the first time. This information is a useful foundation for studying other percussion instruments.

“It could allow researchers to explore how modifications in mounting or other characteristics influence sound production,” Pavill said.

Source: “The effect of mounting conditions on the vibration and directivity patterns of the glockenspiel,” by Hanna M. Pavill and Micah R. Shepherd, JASA Express Letters (2025). The article can be accessed at https://doi.org/10.1121/10.0039258 .