After fixing your speakers you might consider scenting the area around your speakers with some sort of citrus scent(cats detest citrus--ever let a cat smell an orange?). Pet stores sell this type of thing in a spray bottle that you might want to spray around the drivers--I doubt it will hurt the drivers(definately not worse than the cats) and once the cats get the idea they won't go near your speakers anymore. And don't forget the good, old-fasioned spraying cats with the waterbottle when you catch them in the act. Best of luck.
Tim
Tim