Is much excited by total theatre (5,4)
I believe the answer is:
Here is my best explanation:
'theatre' is the definition.
(music hall is a kind of theatre)
'is much excited by total' is the wordplay.
'excited' indicates an anagram.
'by' means one lot of letters go next to another.
'total' becomes 'all' (I've seen this before).
'ismuch' with letters rearranged gives 'musich'.