Contribution from spectacular gong in slow movement (5)
I believe the answer is:
largo
'slow movement' is the definition.
(I've seen this before)
'contribution from spectacular gong in' is the wordplay.
'contribution from' indicates a hidden word (the concealed answer 'contributes' to the clue).
'LARGO' is hidden in the letters of 'spectacular gong in'.
(Other definitions for largo that I've seen before include "taking it steady" , "Deliberately" , "Slow movement in music" , "Moderately slowly" , "Broad and slow (mus.)" .)