Sabine Reverberation Time

Sabine’s reverberation-time formula estimates how long it takes sound energy in a room to drop by 60 dB after the source stops. It comes from a simplified energy-balance model: larger rooms store more sound energy, while more absorbent surfaces remove that energy faster, so reverberation time grows with volume and shrinks with total absorption. The constant 0.161 is specific to SI units and arises from the speed of sound and the conversion between energy decay and decibels in Sabine’s derivation.

Use this formula when designing or evaluating rooms where clarity and echo matter, such as concert halls, classrooms, studios, lecture rooms, and theaters. It is most appropriate for moderately diffuse fields and surfaces with relatively even absorption, not for highly irregular spaces or very small, very absorptive rooms.

• Using surface area instead of total absorption in sabins
• Forgetting that the 0.161 constant is for SI units only
• Applying the formula to a non-diffuse room where reflections are highly uneven