Buzzing after cloth around cone cracked


A few weeks ago I hooked up my Dad's old speaker set to a Sonos Amp. They are Bose 601 Series III stereo speakers. They were working fine until I (it was probably stupid, I know) turned the Bass to max, put the volume at 75% (125W Amp) and played everything that came up when I googled "Songs with the heaviest bass". Well, after 20 minutes or so, one of the speakers started to buzz all of sudden on all the mid frequencies (most of the speakers have cracked cloth but the mid was the first to be noticed). When I looked under the dust cover, the soft material between the edge of the cone and the speaker box/housing was cracked. Whenever I rest my finger on the cone, it stops buzzing. Being that my amp couldn't come close to blowing these speakers on max, I assume it happened because the cloth became brittle with age.

Is there anyway to fix this? Or, more preferably, what is the part called exactly and can I buy it? It doesn't seem like it would be very expensive to replace and these are nice speakers.

Thank you very much for your help
ethan1215
Possibly. In any case I'll be getting a dedicated woofer so I can ruin my hearing without ruining my speakers. Speaking of that, what do you think a good cross over frequency would be for the sub?
Bose has never been very good about giving out frequency responses for their speakers, but I would think somewhere between 60 hz-80 hz would work well.
You do know the speakers are toast, right? Because I get the impression maybe you are gonna try and replace the surrounds. Which will be a waste of time and money. 

The buzzing you heard was the voice coils rubbing in the gap. Once that happens they are no longer perfectly round, and so even if the suspension and alignment are somehow still okay the voice coil isn't and will resume buzzing and scraping even with new surrounds. The only question is howl loud and how soon.  

But hey, look on the bright side- no more Bose!