Calm musical offering, by the sound of it (5)
I believe the answer is:
peace
'calm' is the definition.
(peaceful situation)
'musical offering by the sound of it' is the wordplay.
'musical offering' becomes 'piece' (I've seen this in another clue).
'by the sound of it' shows a homophone (sound like).
'piece' sounds like 'PEACE'.
(Other definitions for peace that I've seen before include "State of freedom from war" , "Quiet - lack of warfare" , "Absence of conflict" , "Quiet companion" , "Calm, serenity" .)