Love very loud group's counterbalance (6)
I believe the answer is:
offset
'counterbalance' is the definition.
(synonyms)
'love very loud group's' is the wordplay.
'love' becomes 'o' (In tennis, 'love' means 'zero').
'very loud' becomes 'ff' (musical abbreviation).
'group' becomes 'set'.
'o'+'ff'+'set'='OFFSET'
(Other definitions for offset that I've seen before include "Place at an angle to the main alignment" , "Place out of line" , "Compensate(d) for" , "Amount by which something is out of line" , "Compensation; printing technique" .)