0bassbindevil 10 years ago ReplyUpvoteSubwoofers are just air pumps, so if you can make a stiff airtight seal, I don't see why it shouldn't work. On a paper cone, try some stiff cardboard, and attach it with white glue, like Weldbond. It would be good to clamp it in place while it dries... that's a little tricky. Maybe small powerful magnets, like the ones on dangerous toys, or (maybe the best) a needle and thread to sew it on. With a plastic cone, cut a patch from flexible plastic like the lid of a yogurt tub. Hot glue may work, or silicone adhesive (RTV).