Cutting room, initially in bar (7)
I believe the answer is:
excerpt
'cutting' is the definition.
(I've seen this before)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for excerpt that I've seen before include "Piece (of music or book)" , "Literary taste" , "Passage from book, play etc" , "Extract from book or film" , "newspaper clipping" .)