Singer brings in right instruments (5)
I believe the answer is:
brass
'instruments' is the definition.
(I've seen this before)
'singer brings in right' is the wordplay.
'singer' becomes 'bass' (bass is a kind of singer).
'brings in' means one lot of letters goes inside another.
'right' becomes 'r' (common abbreviation).
'bass' enclosing 'r' is 'BRASS'.
(Other definitions for brass that I've seen before include "Alloy of copper and zinc" , "Nerve (but not of steel!)" , "Rhino" , "some musicians!" , "section of orchestra" .)