Beams put up in auditorium (4)
I believe the answer is:
rays
'beams' is the definition.
(rays of light)
'up in auditorium' is the wordplay.
'up' becomes 'raise' (I've seen this in another clue).
'in auditorium' indicates a 'sounds like' (homophone) clue (as the word might sound to an audience).
'raise' is a homophone of 'RAYS'.
'put' is the link.
(Other definitions for rays that I've seen before include "Beams - fish" , "shafts" , "Fish with wing-shaped fins and long tails" , "we hope to catch occasionally out of the blue?" , "Flat fish" .)