What is Timbre?
How are these differences made?
Here are a few words commonly used to describe either timbre or tone quality.
Reedy Brassy Clear Bright
Focused or unfocussed Breathy Dark
Rounded Piercing Strident Harsh
Warm Mellow Resonant Heavy
Having much, little, or no vibrato (a controlled wavering in the sound); or narrow or wide, or slow or fast, vibrato