Quality of sound from saxophonist on euphonium? (4)
I believe the answer is:
tone
'quality of sound' is the definition.
(I've seen this before)
'from saxophonist on euphonium?' is the wordplay.
'from' says the answer is hidden in the clue.
'TONE' is hidden within 'saxophonist on euphonium'.
(Other definitions for tone that I've seen before include "Pitch or timbre" , "feel" , "Note; note (anag.)" , "Quality of a musical or vocal sound" , "A pitch of note" .)