Musical ensemble needed for large party (3,4)

I believe the answer is:

big band

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'musical ensemble' is the definition.
'big band' can be an answer for 'ensemble' (thesaurus). I am unsure of the 'musical' bit.

'large party' is the wordplay.
'large' becomes 'big' (synonyms).
'party' becomes 'band' (I can't explain this - if you can you should give a lot more credence to this answer).
'big'+'band'='BIG BAND'

'needed for' acts as a link.

Can you help me to learn more?

(Other definitions for big band that I've seen before include "Dance orchestra of 30s" , "Large group of musicians" , "Large jazz ensemble" .)

I've seen this clue in The Irish Times.

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