The intensity of a sound wave is defined as the amount of sound energy passing through a unit area per second.
The intensity of sound is given as:
I=P/A |
Where,
- I is the sound intensity
- P is the acoustic power
- A is the normal area to the direction of propagation
Loudness:
Loudness is a measure of the response of the ear to the sound. Its amplitude defines the loudness of a sound. The amplitude of a sound decides its intensity, which is perceived by the ear as loud.
Therefore, the following is the table that explains the difference between loudness and intensity:
Loudness | Intensity |
Loudness is the measure of the response of the ear to the sound. | Intensity is the sound power per unit area. |
Loudness is measured in decibels. | Intensity is measured in Watt per meter square. |
Loudness is dependent on the sensitivity of the human ears. | Intensity is independent of the sensitivity of the human ears. |
Loudness is a subjective quantity. | Intensity is an objective quantity. |