Your right most of the original drivers were Gefco. Another thing I would due is remove the toggle switch from the rear of speakers. Basically that is a internal jumper between the speakers post and the switch is the weak link. Then use external jumper wire between the post. The one pair I had, when I first got them, the switch did nothing. I could hook the speaker wire coming from the amp to the bottom pair of post, move the switch nothing changed. Put the speaker wire to the top set of post, move the switch, nothing changed. I ended up just removing it and filling the hole.