Enthusiast cut trial recording (4)
I believe the answer is:
demo
'trial recording' is the definition.
'enthusiast cut' is the wordplay.
'enthusiast' becomes 'demon' (demon can mean an enthusiast for something).
'cut' means to remove the last letter.
'demon' with its final letter taken away is 'DEMO'.
(Other definitions for demo that I've seen before include "Eg, protest march" , "Public protest meeting" , "Protest (abbr)" , "exhibit" , "Tape sent to recording studio" .)