They are old vintage alnico 14" JBL drivers. I choose them because I am a vintage JBL nut and I am a sucker for 4" edgewound voice coils! They also would give me good bass response in a smaller box. My original premise was an honest to god 30Hz. They are tunned with -3db @ 32Hz and -6@ 30HZ with no room gain or boost from the subwoofer amps. You can still get LE14H which would be better with lower fs and higher x-max as a closeout at Speakercity. They are less sensitive than the LE14A'S at 91 as oppossed to 93 for the older driver. I was originally concerned with them keeping up with the 4655 because of the 100db 1 watt sensitivity. There was no problem at all at any tolerable listenning levels. Just get a copy of Win ISD or download what Wayne has at the Pi website. He has Box Plot and Pi Align and lots of other great stuff if you have not been to his site. Just figure out how big a cabinet you can build and start trying the drivers in the preloaded driver libraries and go from there.