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Sound - Reverberation Time

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Reverberant sound is the collection of all reflected sounds.

The Reverberation Time - Ta - for a room is the time it takes before the sound pressure level has decreased with 60 dB after the sound source is terminated and can be calculated as

Mean sound absorption coefficient αm <= 0.35:

Ta = 0.16 V / A                     (1)


Ta = reverberation time (s)

V = room volume (m3)

A = the total sound absorption of the room (m2 Sabine)

Download and print Sound Reverberation Time chart

Mean sound absorption coefficient αm > 0.35:

Ta = 0.16 V / [(A /αm)ln (1 / (1 - αm))]                       (2)

Note! The sound absorption of the room - A - vary with sound frequency, and so do the reverberation time - Ta.

Recommended Sound Reverberation Times for some typical Rooms

Sound - Reverberation Time
Recommended Reverberation Time - Ta - (s)
Room Volume
Conference room, school, cinemaConcert Hall, Normal MusicChurch, Organ Music
10000 1.0 1.5 2.0
1000 0.8 1.3 1.6
100 0.6 1.1 1.2

Example - Sound Reverberation Time for a Room

The sound reverberation time for a room with mean sound absorption coefficient 0.2, total sound total sound absorption 12.2 m2 Sabine and room volume 4 m3 - can be calculated with equation (1) as

Ta = 0.16 (4 m3) / (12.2 m2 Sabine)

    = 0.05 s

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Related Topics


Room acoustics and acoustic properties, decibel A, B and C, Noise Rating (NR) curves, sound transmission, sound pressure, sound intensity and sound attenuation.

Related Documents

Propagation of Sound Indoors - the Room Constant

In a room the sound or noise will reach the receiver as direct and reverberant sound.

Sound - Room Absorption Characteristics

Mean absorption coefficients and reverberation times in typical rooms.

Sound - Room Absorption Coefficients

Room sound absorption and absorption coefficients for common materials like plaster walls, brickwork, plywood panels and more.

Sound - Room Attenuation in Direct Sound Fields

Room size, absorption characteristics - and attenuation in direct sound fields.

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