Harry, say quiet animal (6)
I believe the answer is:
potter
'harry' is the definition.
(I've seen this before)
'quiet animal' is the wordplay.
'quiet' becomes 'p' (music symbol for 'piano', ie soft or quiet).
'animal' becomes 'otter' (I've seen this before).
'p'+'otter'='POTTER'
'say' acts as a link.
(Other definitions for potter that I've seen before include "Maker of earthenware dishes" , "The Harry - - books" , "Harry, Dennis or Beatrix?" , "Mess (around)" , "Maker of earthenware vessels" .)