Item of music, quiet, on the radio (5)
I believe the answer is:
piece
'item of music' is the definition.
'piece' can be an answer for 'music' (piece is a kind of music). I'm not certain of the 'item of' bit.
'quiet on the radio' is the wordplay.
'quiet' becomes 'peace' (I've seen this before).
'on the radio' shows a homophone (sound like).
'peace' sounds like 'PIECE'.
Can you help me to learn more?
(Other definitions for piece that I've seen before include "king or queen?" , "Bit; item" , "Unpleasant character" , "Portion, coin, item" , "man on board" .)