Tone Colour is the description of sound.
Here is a great explanation of what Tone Colour is:
Tone Colour Words:
Mellow, sweet, warm, smooth.
Distorted, aggressive, dark, muddy,
Bright, pure, piercing, clear
Majestic, Grand, Booming, Strong, powerful
Breathy, Airy, Muffled, Muted
electronic, Beeping, artificial
Nasal, reedy, eerie
Dry, percussive, rumbling
Piercing, Metallic, Brassy