Bound to sound like a current variation (4)
I believe the answer is:
tied
'bound' is the definition.
('tie' can be a synonym of 'bind')
'sound like a current variation' is the wordplay.
I cannot really see how this works, but
'current' could be 'i' (symbol for electric current) and 'i' is present in the answer.
The remaining letters 'ted' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
'to' acts as a link.
Can you help me to learn more?
(Other definitions for tied that I've seen before include "Linked; restricted" , "(Of pub) controlled by a brewery" , "Drawn" , "have equal scores" , "Bound; placed equal" .)