More than one concert hall song with alto (4)

I believe the answer is:

odea

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'more than one concert hall' is the definition.
(I've seen this in another clue)

I don't understand the rest of the clue.

(Other definitions for odea that I've seen before include "halls giving entertainment" , "Old theatres" .)

I've seen this clue in The Times and The Sunday Times.

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