Level 42, say, with bass up front (4)
I believe the answer is:
band
'level 42 say' is the definition.
(I know that Level 42 is a band)
'with bass up front' is the wordplay.
'with' becomes 'and'.
'bass' becomes 'b' (abbreviation in music).
'up front' says to put letters next to each other.
'and' put after 'b' is 'BAND'.
(Other definitions for band that I've seen before include "Group; frequency range" , "troop" , "Ring or musical group (4)" , "Pop group, perhaps" , "Music ensemble" .)