While sound returns, extremes of volume contained (4,2)
I believe the answer is:
even as
'contained' is the definition.
I know nothing about this answer so I cannot judge whether it can be defined by this definition.
'while sound returns extremes of volume' is the wordplay.
I cannot quite see how this works, but
'while' could be 'as' and 'as' is found within the answer.
'volume' could be 'v' (abbreviation for volume in book titles) and 'v' is located in the answer.
The remaining letters 'een' is a valid word which might be clued in a way I don't see.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for even as that I've seen before include "a neighbouring number goes cycling?" , "At the moment" .)