Bird in the music room (3)
I believe the answer is:
emu
'bird' is the definition.
(emu is a type of bird)
'in the music room' is the wordplay.
'in' indicates a hidden word.
'EMU' is hidden within 'the music room'.
(Other definitions for emu that I've seen before include "it'll never fly!" , "one offering challenge to Hull?" , "Aussie runner" , "European project" , "Flightless Aus. bird" .)