Sound quality coming from south west? (4)
I believe the answer is:
tone
'sound quality' is the definition.
(I've seen this before)
I don't understand the rest of the clue.
(Other definitions for tone that I've seen before include "Musical sound of note" , "Quality or character of sound" , "Theobald Wolf . . . ." , "Bodily firmness" , "Shade" .)