Interesting speakers alright! The driver compliment looks like reasonably good quality DIY stuff. The woofers, Peerless CC 12"(I believe) are well respected in the DIY community. In a sealed box they have a 3db down of 38.6hz @ .707, but they need 4.7 cu ft EACH to accomplish it!

Maybe that's why those speakers are so large!!

I have a Peerless 10" from the CSX line in my sub, and it works just great!
Rich.