Acoustics of rooms

Advanced

Reverberation time depends on volume and absorption.

Key relationT = 0.161V/A

Reverberation time T = 0.161V/A (Sabine) depends on room volume and total absorption. Concert halls aim for 1.5–2.2 s.

Worked example

V = 3000 m³ and absorption 1500 m²: T = 0.161·3000/1500 ≈ 0.32 s.

Common mistake

Too much reverberation blurs speech.

In more detail

Room acoustics depend on reflections, absorption and standing waves. Good rooms balance these so sound is clear and evenly distributed.

Concert halls are designed with reflective surfaces and absorbers.
Recording studios use absorbers to reduce echoes.
Architects use reverberation time to design concert halls and recording studios with the right amount of echo.

What is reverberation?

The persistence of sound due to repeated reflections in a room.

Why do rooms have standing waves?

Reflections between parallel walls form patterns that boost certain frequencies.

What makes a room echo too much?

Hard, reflective surfaces and large volumes give long reverberation times, so sounds blur together.