The Collapsed Spider We have discussed this in years past, but good advice is that when storing old Alnico #3700 12-inch or 200003-0 Ferrite 12-inch woofers, do no place it magnet-down (or magnet-up) for prolonged periods of time.  This is true also of the AR speaker cabinets themselves using this woofer; i.e., when storing (or mounting) the speaker, do not place or store the speaker cabinet face-up or face-down for long periods of time.  This can result in a condition known as "collapsed s