Note provided by pre-eminent modern composer (10)
I believe the answer is:
minimalist
'modern composer' is the definition.
(minimalism - type of contemporary classical music)
'note provided by pre-eminent' is the wordplay.
'note' becomes 'minim' (minim is a kind of note).
'provided by' is a charade indicator (letters next to each other).
'pre-eminent' becomes 'alist' (the A-list are the pre-eminent members of a field).
'minim'+'alist'='MINIMALIST'
(Other definitions for minimalist that I've seen before include "modern kind of composer" , "artist" , "Deliberately simple or basic" , "abstract art" , "least" .)