Concert hall, empty old one in ruins (5)
I believe the answer is:
odeon
'concert hall' is the definition.
(I know that odeon is a type of concert hall)
'empty old one in ruins' is the wordplay.
'empty' suggests removing the centre.
'in ruins' indicates anagramming the letters.
'old' with its centre removed is 'od'.
'one' anagrammed gives 'eon'.
'od'+'eon'='ODEON'
(Other definitions for odeon that I've seen before include "Place for cinema or musical and dramatic performances" , "Hal" , "music performed here" , "Ancient theatre - modern cinema" , "Do one (anag)" .)