# Reverberation Time Formula, Calculator, Calculation of Effective Absorbing Area

### Reverberation Time Calculator:

If you are interested in room acoustics, you should definitely try this reverberation time calculator. You can use it to define one of the most important acoustic properties of any enclosed space. Reverberation time describes how sound is reflected and propagated in a room. This article will give you an overview of how sound works in enclosed spaces and give you a handy RT60 equation (also known as the reverberation time formula).

We will also give examples of optimal reverberation times in rooms with different purposes.

How to use the reverberation time calculator

• To use the echo time calculator, follow these simple steps:
• Enter the dimensions of the room – length, width and height.
• Enter the dimensions and number of any doors in the room.

Do this for any windows in the room.

If you want to fine-tune the absorption coefficients of room surfaces (including doors and windows), you can activate the Advanced mode of the Reverberation Time Calculator to do so. The reverberation time calculator displays the reverberation time of the room in the last field.

### Reverberation Time Formula

Reverberation time formula is the absorption coefficient of that surface A is equal to the is the effective absorbing area of the room a1, a2 , aand the the area of the specific part of the room surface s1, s2, sa .Hence the Reverberation Time formula can be written as

Effective absorbing area formula=

A=a1 *s1+a2 s2+…….+aa*sa

RT60=0.163V/A

where

V= is the total volume of the room

A=is the effective absorbing area of the room

RT60=is the reverberation time

S=is the area of the specific part of the room surface

A=is the absorption coefficient of that surface

Optimal reverberation Time formulas

Communication T=0.32*log V-0.17

Music performance T=0.45*log v+0.17

Speech T=0.37*log v-0.14

Music reharsel=0.47*log v-0.37

### Example:1

Find the reverberation time of a hall having dimensions 50*70*20 and having the absorption coefficient of 0.25

Given that

Length of hall =50

Width of hall=70

Height of hall h=20

Average absorption coefficient a=0.25

Volume of the hall=l*b*h

=50*70*20=70000

Surface area of the hall s=2(50*70)+(70*20)+(20*50)

=2(3500)+1400+1000)

=11800

Total average absorption is A=0.25*11800=2950

Sabine formula is RT60=0.163 v/A

=0.163*11980/2950

=0.163*4.0610

=0.661s

The reverberation time of hall is0.661 sec

### Example:2

Find the reverberation time of a hall having dimensions 40*30*20 and having the absorption coefficient of 0.30

Given that

Length of hall =40

Width of hall=30

Height of hall h=20

Average absorption coefficient a=0.30

Volume of the hall=l*b*h

=40*30*20=24000

Surface area of the hall s=2(40*30)+(30*20)+(20*40)

=2(1200+600+800)

=5200

Total average absorption is A=0.30*5200=15600

Sabine formula is RT60=0.163 v/A

=0.163*5200/15600

=0.163*0.333

=0.054s

The reverberation time of hall is0.661 sec