Direct-sounding channel (6)
I believe the answer is:
strait
'channel' is the definition.
(I know that strait is a type of channel)
'direct-sounding' is the wordplay.
'direct' becomes 'straight' (similar in meaning).
'sounding' indicates a 'sounds like' (homophone) clue.
'straight' is a homophone of 'STRAIT'.
(Other definitions for strait that I've seen before include "Narrow sort of traits (6)" , "Narrow waterway" , "Narrow - artist (anag)" , "Hardship - narrow passage of water" , "Difficult state for artist" .)