Quiet deed brings agreement (4)
I believe the answer is:
pact
'agreement' is the definition.
(pact is a kind of agreement)
'quiet deed' is the wordplay.
'quiet' becomes 'p' (music symbol for 'piano').
'deed' becomes 'act' (I've seen this before**).
'p'+'act'='PACT'
'brings' is the link.
(Other definitions for pact that I've seen before include "Formal agreement between parties or states" , "Treaty, formal agreement" , "deal" , "International treaty" , "Agreement, bargain" .)