Loudness is that property of sound which enables us to distinguish between a faint and a loud sound. It depends on the intensity of sound waves.
Factors on which loudness depends:
(i) Area of vibrating body:
The larger the area of the vibrating object, the louder is the sound produced e.g. a drum gives louder sound than dholes.
(ii) The amplitude of the vibrating body:
If the amplitude of the vibrating object is larger or greater, the louder sound is produced. E.g. A drum struck strongly makes its membranes vibrate with greater amplitude, and produces a louder sound.
(iii) The distance of the source of the sound:
If the lister is far away from the source of the sound, the faint sound is heard, when the source of sound is near, loud sound is heard.