Feeding an ensemble that's very loud (9)
I believe the answer is:
deafening
'very loud' is the definition.
(I've seen this before)
'feeding an ensemble' is the wordplay.
'ensemble' indicates an anagram.
'feeding'+'an'='feedingan'
'feedingan' with letters rearranged gives 'DEAFENING'.
'that's' is the link.
(Other definitions for deafening that I've seen before include "Noisy" , "Very loud" .)