Runs when piano produces rough sound (4)
I believe the answer is:
rasp
'rough sound' is the definition.
(I've seen this in another clue)
'runs when piano' is the wordplay.
'runs' becomes 'r' (cricket abbreviation).
'when' becomes 'as' (eg 'when I walked' means 'as I walked').
'piano' becomes 'p' (musical abbreviation).
'r'+'as'+'p'='RASP'
'produces' is the link.
(Other definitions for rasp that I've seen before include "Abrade" , "Smoother" , "Grate; scrape" , "Harsh noise - file" , "File - berry" .)