Composer changes not one note, ultimately (6)
I believe the answer is:
varese
'composer' is the definition.
(I've seen this before)
'changes not one note ultimately' is the wordplay.
'changes' becomes 'varies' ('vary' can be a synonym of 'change').
'not' indicates named letters should be taken away.
'one' becomes 'i' (Roman numeral).
'note ultimately' becomes 'e' (musical note. I am not sure about the 'ultimately' bit.**).
'varies' with 'i' taken away is 'vares'.
'vares'+'e'='VARESE'
Can you help me to learn more?
(Other definitions for varese that I've seen before include "Italian city" , "European compser" , "Edgar --, composer" , "Dissonant composer" .)