In France, the measurement of the reverberation time is carried out in accordance with the standard NF S 31-057 - Acoustics - Verification of the acoustic quality of buildings (October 1982) or with the standard (which is often preferred) NF EN ISO 3382-2 - Acoustics - Measurement of acoustic parameters of rooms - Part 2: Reverberation time of ordinary rooms (September 2010).

Production of the acoustic field

The acoustic field is usually produced by an omnidirectional pink noise source (interrupted noise method)

Measuring equipment

The acoustic measuring equipment generally consists of a sound level meter (with a microphone) and of a calibrator.

If used, the equipment for measuring the temperature and humidity of the room is often a thermo-hygrometer.

ITS omnidirectionnal
noise source

Transfer and analysis software

A transfer and analysis software is generally used, allowing a deferred exploitation of recordings carried out on site.

Reverberation time (reverberation time) evaluation

The reverberation time is the time needed for the sound pressure level to decrease by 60 dB after the noise source is turned off in a room.

Example of recording of the temporal sound decay allowing the determination of the reverberation time TR for the frequency band 4 kHz (in this case: TR = 0.87 s) with an evaluation range greater than that envisaged in the standard NF EN ISO 3382-2).

reverberation time


A value of the reverberation time too high (illustrating excessive reverberation phenomena) can impair the acoustic comfort in some spaces (given their intended purpose) and (in some cases) conformity.