Shakespeare on singers and singing:

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Shall we clap into't roundly, without hawking or
spitting or saying we are hoarse, which are the only
prologues to a bad voice?
                                        —As You Like It, Act 5, scene iii

Benedick [Aside]
An he had been a dog that should have howled thus,
they would have hanged him;
and I pray God his bad voice bode no mischief.
I had as lief have heard the night-raven,
come what plague could have come after it.
                                        —Much Ado About Nothing, Act 2, scene iii

Don Firth