Audience member somehow riles number inside (8)
I believe the answer is:
listener
'audience member' is the definition.
(I've seen this before)
'somehow riles number inside' is the wordplay.
'somehow' indicates an anagram.
'number' becomes 'ten' (ten is a kind of number).
'inside' is an insertion indicator.
'riles' is an anagram of 'liser'.
'liser' going around 'ten' is 'LISTENER'.
(Other definitions for listener that I've seen before include "One following advice" , "Someone paying attention" , "Difficult Times Saturday crossword" , "Puzzle" , "Person paying aural attention" .)