Voice raised in river brawl? (8)
I believe the answer is:
falsetto
'voice raised' is the definition.
(I've seen this before)
'river brawl?' is the wordplay.
'river' becomes 'fal' (River Fal).
'brawl?' becomes 'setto' (I've seen this in another clue).
'fal'+'setto'='FALSETTO'
'in' is the link.
(Other definitions for falsetto that I've seen before include "Artificial pitch" , "High-pitched male voice" , "Note production" , "High singing method" , "Flat toes (anag.)" .)