Piece of music loud, yet not clear (6)
I believe the answer is:
cloudy
'not clear' is the definition.
(I know this)
'piece of music loud yet' is the wordplay.
'piece of' says the answer is hidden in the clue.
'CLOUDY' is hidden in the letters of 'music loud yet'.
(Other definitions for cloudy that I've seen before include "Blurred" , "Murky or nebulous" , "Not transparent" , "Dull, overcast" , "Obscure" .)