Measure the reverberation in three steps
- Stand in the middle of the room, away from the walls, in the quiet.
- Press “Measure” and wait for the countdown to end.
- Clap your hands once, very loudly (or pop a balloon), then stay silent for a few seconds.
–s
The sound stays on your device: nothing is sent.
No measurements here. Take one in the “Measure” tab, or import a file.
Frequency bands
Listening time after the sound
What the measurement can and cannot do
The method is that of the ISO 3382-1 and 3382-2 standards: integrated impulse response, Schroeder curve, truncation and background-noise correction (Lundeby). But a hand clap has little energy in the low frequencies: at 125 Hz, the margin is often missing. A phone microphone is neither flat nor omnidirectional, and the result changes from one spot to another: the standard asks for an omnidirectional source and several positions. In the low frequencies, a single measurement is uncertain (10 to 15% on T30, 1 to 1.5 dB on C50 in our test bench): take several. The STI shown counts only the reverberation, not the noise or the voice level: the real STI is lower.
The reference values and their sources
The main value is the average of the 500, 1,000 and 2,000 Hz bands, as in the French decree of 25 April 2003 on noise in educational buildings (article 5) and the English guide BB93 (table 6), for furnished, unoccupied rooms. The values quoted come from BB93 (new school buildings, England); the table of the French decree is only published as a facsimile in the Journal officiel, and could not be read.
Where your measurements are
The sound of each measurement (a few seconds around the clap) and its results stay in this browser, on this device: nothing is sent. Export them (.rapidaudio file) to keep them elsewhere or open them on another device.
Audio input and measurement microphone
Device names appear after you first allow the microphone.
The file supplied with a measurement microphone (miniDSP UMIK-1, Dayton EMM-6, calibrated Behringer ECM8000…): lines of “frequency gain_dB [phase]”. The correction is applied before the weightings (sound level meter) and to every band (acoustics). Keep the same gain on the sound card as during calibration.