I have repaired torn speaker cones before, with Nail Polish (not mine, of course! [Linked Image]), to bridge the gap between the tears in the cone.
That used to work with older paper cones, but I've never tried it with the newer multi-chemical cones.
BTW, my G/Friend used to get really annoyed to apply her Nail Polish and there would be small paper fragments in it, I can't think where they came from, there must have been a "paper storm" while she had the bottle open!. [Linked Image]