I've never blown a speaker myself, but
always wondered at the flopping cones I've seen on used and junk
speakers. At the last big trash pickup, I saw a beautiful set of Boston
Acoustics A70 speakers with flopping cones. I thought they might
be worth reconeing, so I picked them up and brought them home.
I found out two things researching speakers. The better speakers have a
foam surround to make them more responsive. After a long time,
the foam gives up, and that's what I saw as blown speakers. I
also found that the reason MY speakers had never had that happen is
that they weren't good enough to have that surround.
Refoaming a speaker professionally is only about half of having the
speaker completely reconed. But seemed a lot easier, and kits and
supplies are available!

Somebody took good care of these, but they weren't speakers anymore!

That's what they look like out of the cabinet. I was surprised to
find they were late 1982 manufacture.

Here's almost half way through the process. I've already replaced
the surround on the right, and the one on the left is cleaned up and
ready to repair.

Shows the glue on the speaker and surround. Also the awful mess
that you make.

Back together and sounding good. I could do it quicker and
better next time.
I'm not trying to show all the steps of replacing the surround, just
that
it can be done. Took about $20 and a couple of hours work.
I got my kit from
http://www.wooferrepair.com
and it included all the parts, most of the supplies, and both written
and video instructions. The video was just like having a buddy
over to the house to walk you through it the first time!