Rich performance with old singers (5)
I believe the answer is:
choir
'singers' is the definition.
(group of singers)
'rich performance with old' is the wordplay.
'performance with' indicates anagramming the letters.
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'rich' with its letters mixed up with 'o' makes 'CHOIR'.
(Other definitions for choir that I've seen before include "Religious chorus, perhaps" , "set of singers" , "Chorus in church" , "warblers" , "Vocal group" .)