More curious about start of improvisation getting louder (7)
I believe the answer is:
noisier
'louder' is the definition.
('noisy' is associated in meaning with 'loud')
'more curious about start of improvisation' is the wordplay.
'more curious' becomes 'nosier' ('nosy' can be similar in meaning to 'curious').
'about' is an insertion indicator.
'start of' indicates taking the first letters.
The initial letter of 'improvisation' is 'i'.
'nosier' enclosing 'i' is 'NOISIER'.
'getting' acts as a link.
(Other definitions for noisier that I've seen before include "more deafening!" , "More rowdy" , "Perhaps more disturbing" , "More of a racket" , "Louder" .)