Musicians so-so -- bit patchy (7)
I believe the answer is:
oboists
'musicians' is the definition.
(I know this)
'so-so bit patchy' is the wordplay.
'patchy' indicates an anagram.
'so'+'so'+'bit'='sosobit'
'sosobit' anagrammed gives 'OBOISTS'.
(Other definitions for oboists that I've seen before include "Woodwind players" , "Musicians" , "10 across group" .)