what to do with my cat on my speaker grills

Walmart sells a compressed air can with a motion sensor in the pet section. I forget the name of it, but I think it is called Scatttt, or some form of that. It works well, any time the cat gets within the range of the sensor, it blasts a shot of compressed air at the cat, and away they go.

Get a pair of Wilson Watch Dogs.

Anyone see the opening scene in the movie The Book of Eli?

Cats are single minded little beasts. Not really smart, but very clever and willing to take 'risks'.

You may want to check at a pet store. They may have a 'repel' odor treatment.
My MG-1s were so treated by the original owner and my 2-head of cat NEVER went near them in over 15 years. Not ONCE.

Cats DO NOT like CITRUS smell.
Dr. Bronner's Peppermint Castile soap is also on the no smell list. And it is a great shower soap. It is a liquid so dabbing some on a cloth and leaving it next to the speaker may work?

Change the catpacitors in your crossovers.