Sound in English Church — not in the middle (4)
I believe the answer is:
echo
'sound' is the definition.
(echoing is a kind of sounding)
'english church not in the middle' is the wordplay.
'english' becomes 'E' (abbreviation).
'church' becomes 'ch' (common abbreviation).
'in the middle' indicates the central letters.
The centre of 'not' is 'o'.
'e'+'ch'+'o'='ECHO'
'in' acts as a link.
(Other definitions for echo that I've seen before include "Be suggestive of" , "repetitive" , "Reflected radar beam" , "copy" , "One who slavishly copies" .)