# Decibel Comparison Problem

1. Sep 26, 2007

### vertciel

Hello everyone,

Could anyone please show me the appropriate formulas which I need for the following question?

1. How many times louder or softer than sound level of 40 dB is a sound at

a) 68 dB? b) 0.3 dB?

Thank you.

2. Sep 26, 2007

### Staff: Mentor

3. Sep 26, 2007

### vertciel

I know how to calculate the difference in sound level for integers divisible by 10. For example, 60 dB is 10^2 or 100 times louder than 40 dB.

However, I know that I must use logarithms for calculating the difference in sound level for all other integers.

4. Sep 26, 2007

### Staff: Mentor

Well look at the example of 40 dB

I = 10000 I0, or I = $$10^{40dB/10}$$ I0 = 10000 I0

and for 60 dB, I = $$10^{60dB/10}$$ I0 = 106I0

and for 68 dB, ____________?

5. Oct 3, 2007

### vertciel

Thank you very much for your help!