Piped down audibly (4)
I believe the answer is:
blew
'piped' is the definition.
'down audibly' is the wordplay.
'down' becomes 'blue' (I've seen this before).
'audibly' indicates a 'sounds like' (homophone) clue.
'blue' sounds like 'BLEW'.
(Other definitions for blew that I've seen before include "Bungled (an opportunity)" , "Sounded (a horn)" , "Squandered" , "Spent recklessly; exploded suddenly" , "Puffed and panted" .)