Channel rough, by the sound of it (6)
I believe the answer is:
course
'channel' is the definition.
(thesaurus)
'rough by the sound of it' is the wordplay.
'rough' becomes 'coarse' ('coarse' is associated in meaning with 'rough').
'by the sound of it' indicates a 'sounds like' (homophone) clue.
'coarse' is a homophone of 'COURSE'.
(Other definitions for course that I've seen before include "fish, possibly" , "Path, track" , "soup?" , "Prescribed number of lessons" , "Source (anag.)" .)