Audibly, second note's the first for composer (5)
I believe the answer is:
bizet
'composer' is the definition.
(I've seen this before)
'audibly second note's the first' is the wordplay.
'audibly' indicates a 'sounds like' (homophone) clue.
'second note's the first' becomes 'b's a' (b, the second note is a, the first).
'bsa' is a homophone of 'BIZET'.
'for' is the link.
(Other definitions for bizet that I've seen before include "French composer of 'Carmen'" , "Georges __; French composer" , "French opera composer, d. 1875" , "Composer of the opera Carmen, d. 1875" .)