Is the Human Body a Sound Absorber?

— Exploring the Role of the Human Body in Anechoic Chambers and Concert Halls —

In acoustic design, the human body is not just a passive listener but also an active element that influences sound.
This article explores how the sound-absorbing characteristics of the human body—including clothing—are taken into account in both concert hall design and the construction of anechoic chambers.

The Human Body Absorbs Mid-to-High Frequencies

The human body tends to absorb sound particularly well in the 500 Hz to 5,000 Hz frequency range. This is because the human body is composed of soft tissues containing a high percentage of water, which efficiently converts sound energy into heat.

Furthermore, clothing also plays a significant role in sound absorption. Materials such as wool, fleece, and cotton are especially effective at absorbing and diffusing high frequencies. As a result, a person wearing clothes acts as a highly effective absorber, especially in spaces like concert halls.

This frequency range includes much of the human voice and many musical instruments, making it critically important in acoustic design. The mere presence or absence of people can significantly change the acoustic environment.

Concert Halls Are Designed with the Audience in Mind

In concert hall design, the acoustic conditions during a full house are typically the reference point. When an audience is seated, the absorption of mid-to-high frequencies increases, altering the reverberation and tonal balance of the space.

To compensate for this, seats are often made with materials that mimic the sound-absorbing properties of the human body, ensuring that acoustics remain consistent even when the hall is empty. Simulation tools and torso-shaped dummy heads are also used to model how sound interacts with the audience’s bodies and clothing during the design phase.

In Anechoic Chambers, Human Presence is a Source of Error

By contrast, in anechoic chambers, the presence of people introduces measurement error and is carefully avoided.

In high-precision environments such as VSAC (Vehicle Semi-Anechoic Chamber) or EAAC (Electroacoustic Anechoic Chamber), measurement conditions must comply with ISO standards (e.g., ISO 3745, ISO 3744), which require a perfectly free sound field that obeys the inverse square law. A person entering the chamber can lower the sound pressure level by 0.5 to 1.5 dB, potentially compromising measurement accuracy.

For this reason, Sonora’s anechoic chambers utilize high-performance absorbing materials such as the Broadband Fractal Wedge (BFW) to create a highly controlled acoustic environment with minimal external influence.

In High Frequencies, Reflection Dominates

Although the body is effective at absorbing mid-to-high frequencies, higher frequencies (such as ultrasonic waves) are more likely to be reflected by the skin or clothing. In testing environments for ultrasonic sensors, the human body is sometimes modeled with dummies to understand and control reflective behavior.

Conclusion: Designing with Human Acoustic Properties in Mind

Concert halls are designed under the assumption that “the audience is part of the sound field.” Anechoic chambers, on the other hand, aim to eliminate any human influence to achieve pure, unaltered measurements.

This contrast reveals an important truth:
How the human body’s acoustic properties are treated directly shapes the purpose and design of the space.

In practical acoustic engineering, it’s essential to account for all elements that affect sound—including the physical and material presence of people. This approach ensures that the space functions as a true acoustic system, optimized for its intended use.

Both the human body and clothing significantly affect how sound behaves in a room. Whether the goal is to enhance natural reverberation or eliminate reflections entirely, understanding human acoustic interaction is fundamental to advanced sound environment design.

If you’d like to supplement this article with technical diagrams or measurement data, or tailor it to a specific application field, feel free to contact us. We’re happy to assist.