Is Amplitude measured in decibels?

Question

So the volume of a sound (i.e. how loud it is) is measured in decibels (dB).

If we look at this sound (that is at a constant frequency) as a sound wave, the louder it is, the higher its amplitude, right?

So is amplitude measured in decibels when it comes to sound waves?

Answer 1

Sound is characterizes by :

- power level with dB scale 10log P/Pref (being Pref 10^-12 watt)

- pressure level with dB scale 20log Pr/Pr ref (being Pr ref 20^-6 Pa)

Answer 2

Strictly - No.



Loudness is directly related to the energy (or power) of a sound. The amplitude is, for a sound wave, usually the movement of the molecules or the magnitude of the pressure difference due to the sound. If the amplitude doubles, the intensity increases four times, so the loudness increases four times.



Just to confuse you, because the decibel is a logarithmic quantity, the loudness will increase by 6 decibels.



So you are right that loudness is measured in decibels. And you are right that the loudness depends on the amplitude. But amplitude is not measured in decibels.



It is a bit like saying that amount of water in a can depends on the size of the can. Yes it does, but if you have two cans and one is twice as large, in all directions, as the other, then the larger one does not contain twice as much water as the first, but eight times as much.

Answer 3

90degrees without a doubt if we don't forget sinusoidal alerts, one in sine wave and different is a cosine wave .Each alerts are equal but only change is they have a segment shift of 90degrees so integrating or differentiating one will effect within the other variety ...... Practice a sine wave to an integrator or a differentiator to see the result u will find a segment shift of 90degree

Answer 4

with regard to frequency different agencies have different gains vs freq on the equipment they use to measure sound intensity

look up a-weighting

Answer 5

Usually, yes.