Gather, we hear, to see band (5)
I believe the answer is:
troop
'gather' is the definition.
(thesaurus)
'we hear to see band' is the wordplay.
'we hear' indicates a 'sounds like' (homophone) clue.
'to see band' becomes 'troupe' (I've seen this before).
'troupe' sounds like 'TROOP'.
(Other definitions for troop that I've seen before include "Squad" , "musical group perhaps" , "Parade" , "Flock, large group" , "Military body" .)