Sound producer hard to ignore? Hard to avoid several notes (5,4)

I believe the answer is:

vocal cord

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'sound producer' is the definition.
Although both the answer and definition are singular nouns, I cannot see how they can define each other.

'hard to ignore? hard to avoid several notes' is the wordplay.
I cannot quite understand how this works, but
'notes' could be 'ca' and 'ca' is found within the answer.
This explanation may well be incorrect...

Can you help me to learn more?

I've seen this clue in The Times.

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