Making 150 head away from audience (8)
I believe the answer is:
clearing
'making' is the definition.
('clear' can be a synonym of 'make')
'150 head away from audience' is the wordplay.
'150' becomes 'cl' (roman numerals).
'head away from' means to remove the first letter (I've seen 'heading away from' mean this).
'audience' becomes 'hearing' (synonyms).
'hearing' with its first letter taken off is 'earing'.
'cl'+'earing'='CLEARING'
(Other definitions for clearing that I've seen before include "becoming brighter" , "one among trees" , "Glade; declaring innocent" , "Tract of land with no trees in a wooded area" , "Sort of bank" .)