How do I remove the woofer from ads 300 speaker?

So I found a pair of ads 300s at the take it or leave it section of the dump...I mean solid waste disposal and recycling center... along w an NAD 2200.  The amp and one of the speakers work just fine, but the other appears to have a bad woofer.  No sound from the woofer (tweeter is fine) and when I gently push in on the woofer cone it scrapes a bit.  However I can't figure out how to get the darn thing out.  I removed the 4 screws folding the metal frame to the baffle, but no dice.  No apparent way to remove the terminal cup on the back either.  Google has been no help so far.  Any ideas?