Per-octave reverberation time with Sabine and Eyring, using a library of typical absorption coefficients.
m
m
m
Treatment, furnishing and openings
Each item replaces the same area of the surface it is placed on.
RT60 mid (500 Hz – 1 kHz, Sabine)
0.828s
Room volume
72.9m³
Decay rate (mid)
72.5dB/s
Band
Absorption A (m²)
Mean α
Sabine (s)
Eyring (s)
Decay (dB/s)
125 Hz
4.1
0.037
2.86
2.81
20.9
250 Hz
8.87
0.08
1.32
1.27
45.4
500 Hz
13.1
0.12
0.897
0.843
66.9
1 kHz
15.5
0.14
0.759
0.705
79.1
2 kHz
16
0.14
0.733
0.679
81.8
4 kHz
16.6
0.15
0.708
0.654
84.7
Absorption coefficients are typical published values; actual products differ. For critical rooms use manufacturer data or measurements.
How it works
RT60 is the time for sound to decay by 60 dB. It grows with room volume and shrinks with absorption. Sabine's formula suits live rooms; Eyring's is more accurate when the average absorption is high, as in studios.
Materials absorb very differently at 125 Hz and 4 kHz, so the calculation is done per octave band. Pick materials for floor, ceiling and walls, then add treatment, curtains or audience; each item replaces part of the surface it sits on.