High treble producing great number (6)

I believe the answer is:

belter

I'm a little stuck... Click here to teach me more about this clue!

'great number' is the definition.
The definition suggests a singular noun which matches the answer.

'high treble' is the wordplay.
'high' is an anagram indicator (like drunk).
'treble' is an anagram of 'BELTER'.

'producing' acts as a link.

Can you help me to learn more?

I've seen this clue in The Times.

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