When Screamer dropped by to say hello, I looked up some of his posts, and found this.
Here is a page where you can click on sound files that cats dislike, a loud harmonica and a Hissss! : cats dislike these sounds:
I don't know if it is bad to annoy cats. If anyone plays the sound files while a cat is near, you can report the reaction.
I think that if Kitten plays the files, there could hardly NOT be a cat near, since I understand she has several. (No, she is not one of those people you read about with hundreds of cats. She is just big-hearted, especially when it is a rescue situation, and has more than most people.)
The hiss didn't get a reaction.
The harmonica certainly woke him up!