I'm thinking of blasting harmonica music at my cat to get him off my bed
Please don't do that. What will you accomplish by doing that?
I will teach the cat a lesson to stay away from the bed.
Blasting music at the cat is borderline animal abuse and at the very least it is cruel to your pet. I don't want to see you doing that, as the cat could be traumatized by your actions..
My cat is not a human, it needs a little aggression to understand what I want.
Aggression towards your cat by playing loud harmonica music at it will only teach the cat to be aggressive in turn. One day you may wake up to find the cat tearing up things in your house to deal with the trauma you created in your pet.