Singer's note for the audience (5)
I believe the answer is:
tenor
'singer's' is the definition.
(tenor is a kind of singer)
'note for the audience' is the wordplay.
'note' becomes 'tenner' (a tenner is a 10 pound note).
'for the audience' indicates a 'sounds like' (homophone) clue.
'tenner' sounds like 'TENOR'.
(Other definitions for tenor that I've seen before include "Big bell" , "Carreras, for example" , "Male voice of high pitch, like Luciano" , "One singing" , "High voice - low bell" .)