RT60 Measurement

RT60 measurement is the process of determining the reverberation time of a room according to ISO 3382-2:2008. The procedure involves exciting the room with a sound source (loudspeaker playing swept sine or interrupted noise, or an impulsive source like a starter pistol) and recording the response at multiple positions. The impulse response is processed using Schroeder backward integration to obtain decay curves per octave band, from which T20 or T30 values are extracted and extrapolated to a 60 dB range. A minimum of two source positions and three receiver positions (six combinations) is recommended for spatial averaging. Results are reported per octave band from 125 Hz to 4000 Hz, with the mid-frequency average (500–1000 Hz) commonly used as a single descriptor. Field measurements should be conducted in the furnished but unoccupied state unless otherwise specified by the applicable building regulation.