Reverberation Time –

Reverberation time is defined as time interval between the initial direct note up to minimum audibility level.

Sabine’s Formula –

It can be stated as,

$ T=(0.161) \dfrac {V}{A}$

where, T = Reverberation time,

0.161 = constant of proportionality

V = volume of hall

A = Overall absorption

$\sum\limits _{i=1}^naS = a_1S_{1} + a_{2}S_{2}+a_{3}S_{3} …. +a_{n}S_{n}$

Here : a1, a2, ..... an absorption coefficient for each reflecting surface & S1, S2, ..... Sn are corresponding areas.

We can use the above formula for controlling T as follows –

1) As far as possible the volume V must be controlled (by keeping height h low).

2) Since T is more for more reflective surface which are smooth, we may use rough walls & ceilings.

3) We must use walls & ceiling materials that good absorption coefficients.