Question

what is the quality or timbre of sound?

Answer 1

characteristics of sound which enables us to recognize it and as sings its source  is called the quality or timber................................

Answer 2

  The unique characteristics of the sound which allow us to recognize the sound (voice/vibration/disturbance/music/noise) is the quality or timbre of sound.
 
  The quality or timbre allows us to identify the sound with a person, event, instrument etc.