My Spica TC 50 is alive and well:

You may remember back in late July, I sat down one evening to listen to my vintage Spica TC 50s. To my dismay the right speaker was making a fluttering buzzing sound. I did take note that my son had left one of his metal rock band CD's in the player. I quickly posted a plea for help to the AK speaker forum. It was great to see the response of so many that gave me things to try to pin point where the problem was. Special thanks to Pete B. and Spkrdtr (Carl at Carl's Custom Loudspeakers) for all their insight. I had decided with the age of the speaker it probably didn't make sense to repair it. Spkrdtr told me that he had fixed several TC 50's and was pretty sure he could bring mine back to life. After flip flopping back an forth, I finally sent it off. It wasn't to long and this little box arrived at my house. Yes it was my repaired woofer. That same night I pulled out the soldering iron, silver solder and mounted the woofer back in the cabinet. I was a little apprehensive when I pushed the play button with Reference Recording's Michael Garson "Serendipity" acoustic jazz cued up. The first notes that touched my ears caused a response of Ahhhhhhhhhhh, beautiful! Thanks again to everyone and especially Carl at classicloudspeakersservices.com (is it OK to give kudos) for giving my Spica woofer new life.

Thanks Mgardner. Here is the original thread he referred to
http://www.audiokarma.org/forums/showthread.php?t=243494&highlight=spica

The problem was not a loose surround or spider. It was my second thought. A damaged VC former. I have encountered and repaired this defect now on a few different woofer types - mostly those with thin metal VC formers and very loose suspensions (i.e. AR3a, Advent and Spicas).

Below is a picture of Mgardner's damaged former. It shows the back edge rolled over just a bit. However, it's enough to reduce the ID of the former enough so it rubs on the pole piece; particularly if you push on the spider in the right spot like mgardner did in the earlier thread. The defect was most likely caused by playing music very loud with lots of heavy bass notes thus causing the stroking of the voice coil rearward to the extent it slams against the back plate of the magnet assembly, thus deforming the delicate former.