Decibel Comparison Formulas for Sound Levels

[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.

 

[Astronuc]

What is the definition of Bel or decibel?

Presumably the definition and appropriate equation are in one's textbook or classnotes?

Otherwise, please refer to - http://hyperphysics.phy-astr.gsu.edu/hbase/sound/db.html

 

[vertciel]

Thanks for your reply.

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.

 

[Astronuc]

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, ____________?

 

[vertciel]

Thank you very much for your help!