Logarithms are used to measure the “loudness” of sound. Decibels (dB) are logarithmic units used to describe a ratio of two levels of intensity or pressure. The difference between two levels of sound pressure ( P1 and P2 ) is defined as 10 log(
)dB. Usually, when decibels are used to describe just one sound, it is assumed that that sound is being compared to a reference level of 20 micropascals. Homework Help ✎
How many decibels correspond to doubling the pressure of a sound?
What is the sound pressure of a noise described as 60 dB?
What does 0 decibels mean?
How many times more pressure is in a sound of 40 dB than of 20 dB?
10 log(2) ≈ 3.0
P = 20 · 106 = 2 · 107
The sound ratio is 1.
100 times more pressure.