Modulation of the voice (7)
I believe the answer is:
cadence
'modulation of the voice' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for cadence that I've seen before include "Final musical sequence" , "Inflection; voice pitch fall" , "Vocal modulation or inflection" , "Lilt" , "that may be perfect for musicians" .)