Let room out for musical effect (7)
I believe the answer is:
tremolo
'musical effect' is the definition.
(I've seen this before)
'let room out' is the wordplay.
'out' indicates an anagram (out can mean wrong or inaccurate).
'let'+'room'='letroom'
'letroom' is an anagram of 'TREMOLO'.
'for' acts as a link.
(Other definitions for tremolo that I've seen before include "Vocal vibrato -- lot more (anag)" , "Musical shake" , "effect of repeated bowing" , "Violin's rapid repetition of a single note" , "Quivering effect (in music)" .)