Sent remit with British sound (6)
I believe the answer is:
timbre
'sound' is the definition.
(a particular musical sound or tone)
'sent remit with british' is the wordplay.
'sent' indicates an anagram (send can mean to excite or stimulate).
'with' means one lot of letters goes inside another.
'british' becomes 'b' (abbreviation e.g. in 'BBC').
'remit' anagrammed gives 'timre'.
'timre' going around 'b' is 'TIMBRE'.
(Other definitions for timbre that I've seen before include "The distinctive property of a voice" , "Quality of voice, sounds wooden" , "Distinctive sound quality" , "The quality of the speaking voice" , "colour we hear" .)