This is what I was thinking too. My other pondering was since these were cloth and never foam could I not just use like and artist canvas material? I don't know how to crimp it like the original, heres a photo I stole off the bay. If you look at the original the surround isn't one piece rather 6 pieces. My worry about making one from foam is that the ring may want to straighten back once on the cone. Though I could glue it to the back of the cone on the angle then attach to the basket....why does it have to be 30"