1. Loudness 

2. Pitch 

3. Quality or Timbre 

1. Loudness: 

• It is defined as the characteristic of a sound that enables us to distinguish a weak or feeble sound from a loud sound. 
• The loudness of a sound depends on its amplitude. 
• Higher the amplitude louder will be the sound and vice-versa. 
• When a drum is softly beaten, a weak sound is produced. However, when it is beaten strongly, a loud sound is produced.
• The unit of loudness of sound is decibel (dB).

2. Pitch: 

• The pitch is the characteristic of sound that enables us to distinguish between a flat sound and a shrill sound. 
• Higher the frequency of sound, higher will be the pitch. High pitch adds shrillness to a sound. 
• The sound produced by a whistle, a bell, a flute and a violin are high pitch sounds.

3. Quality or Timbre: 

• The quality or timbre is the characteristic of sound that enables us to distinguish between two sounds that have the same pitch and amplitude
• For example in an orchestra, the sounds produced by some musical instruments may have the same pitch and loudness.