How about a metaphor?
She is an evil Carol Channing.
Limerick:
There was once a hag named Susan
Whose main occupation was boozin'.
She just wasn't planning
To sound like Carol Channing
But that is the voice she was usin'.
Haiku:
Have you heard Susan?
She sounds like Carol Channing.
What a grating voice.
Whoa. Inspired.