[Weekly Science Popularization] The Technical Architecture of Reverberation Time Control

Why does the music flow so naturally while the dialogue remains clear and distinct? The key lies in the precise control of reverberation time. This article will discuss reverberation time control techniques.

Reverberation time refers to the time required for the sound pressure level in a room's diffuse sound field to decrease by 60 dB after the sound source stops emitting sound. Its control technology is primarily based on the Sabine formula: T60 = 0.161V/A = 0.161V/αS

T60 represents the reverberation time (s); V represents the room volume (m³); A represents the total sound absorption (m³); S represents the total surface area of ​​the sound absorber (m²); α represents the average sound absorption coefficient of the sound absorber.

Sound absorption and noise reduction are tools for controlling reverberation time. Indoor background noise can be reduced by altering the reverberation time through sound absorption treatment, thereby lowering the noise sound pressure level in the reverberant sound field.

The sound pressure level difference before and after treatment is: ΔLp = 10lg (T_after/T_before). The calculated values ​​of the reverberation time ratio before and after sound absorption treatment and the noise reduction amount are as follows:

The reverberation time (RT60) of a hall is a core indicator for measuring indoor sound quality. Its impact on subjective listening experience is mainly reflected in clarity, fullness, warmth, and spatiality. Excessive reverberation results in a muddy sound with low clarity; moderate reverberation produces a clear, full, and dynamic sound; insufficient reverberation results in a dry sound lacking musicality.

By adjusting the type, area, or location of sound-absorbing and diffusing materials, reverberation time can be precisely controlled, ultimately achieving the goal of reducing environmental noise and improving the acoustic environment.

What standard should the reverberation time of the hall be controlled to?

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