Cat damaged speaker, Help

Silicone will add weight to that section of the surround(not much, but...), and silicone does not adhere well to neoprene anyway. Get some Super Glue/Krazy Glue/cyanoacrylate adhesive, and dab a TINY bit exactly in the center of the cut, with the tip of a toothpick(don't spread the cut). capillary action will carry the adhesive into the cut, and left alone for a few minutes, the repair will be complete.

Cyanoacrylate adhesive, used in minimal amounts, should work well. And for you guys who are suggesting destroying the cat.... you are cruel and crazy. If you have a pet, it's your responsibility to create an environment where they are nurtured and protected. Your cat or dog did not ask to live with you.... YOU decided to invite them into your home and your life. Be responsible !!!! I've had two cats and four dogs with my Vandersteens and tubes.... never any problems. There's enough crazy violence in this world already. Let's at least respect and take care of our pets !

Another vote for the super glue; a little dab with a tooth pic. I prefer the gel type which doesn't run.

Agree with Adam
There is a simple solution that seems to work well for Vandy and Magie or most any speaker owners
Pick up a spray can of Orange Citrus spray from Bed Bathe and Beyond and a couple plastic sandwich bags.
Spray a fair amount into the Baggies and tape each one to the low back side of the speakers.
You can also spray the base low section around the speaker as well.
Cats seem not to like the orange citrus scent but pleasant to most folks with 2 legs.
Cheers Johnnyr

One of many reasons a "no pets" listing is a must when buying a used speaker. If it were my speaker, I'd try to replace the driver. If I couldn't, I would let a shop repair it. Just send the driver.

When I had issues with a Legacy 20/20 tweeter, they repaired it for me free. Even sent out a box built to hold the tweeter correctly free