Expert in sound okayed original recording (4,6)
I believe the answer is:
past master
'expert' is the definition.
(past master is a kind of expert)
'sound okayed original recording' is the wordplay.
I cannot really see how this works, but
'original' could be 'master' (synonyms) and 'master' is found within the answer.
The remaining letters 'past' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
'in' acts as a link.
Can you help me to learn more?
(Other definitions for past master that I've seen before include "Someone with a long and thorough experience in a given activity" , "wizard" , "seen at staff reunions?" , "Person experienced in a particular field" , "Thomas Arnold was" .)