# Sound Level

1. Jan 13, 2008

### ronny45

[SOLVED] Sound Level

1. The problem statement, all variables and given/known data

If sound intensity level is reduced from 90dB to 75 dB, what is the ratio of the new sound level to the old?

2. Relevant equations

Sound Intensity Level = 10 log (I/Io)

3. The attempt at a solution

10 log 90 = 1.954
10 log 75 = 1.875

1.875/1.954 = .956
This probably goes against every physical law that exists, but it's all I've come up with so far. Help, please!

2. Jan 13, 2008

### weathercheck

Its easy!

Its 1/10^2.5

Sorry that was for me!!

Its 1/10^1.5 for you

90--->75

Mine was 90-65

Last edited: Jan 13, 2008
3. Jan 13, 2008

### ronny45

4. Jan 13, 2008

### weathercheck

This 15 db difference corresponds to a 1.5-Bel difference. This difference is equivalent to a sound which is 10^1.5 more intense. Always raise 10 to a power which is equivalent to the difference in "Bels.

Or less intense in this case thus dividing by 1.

5. Jan 13, 2008

### ronny45

Thank you!

6. Jan 13, 2008

### weathercheck

Now i sent you a pm!! lol