best WOOFER ???

As far as pricing goes I don't see any published numbers. I was reading about the new driver on the "L-A-Driver" page, the top button in the upper right corner of the home page at Belifurari.com, and if you look at the pictures of the driver itself, at the very bottom of that page, it appears that it might be fully hand made. If that is so then I am sure it is not cheap. It kind of reminds me of Feastrex, all hand made and uber-expensive. I was also reading the "Fidelity" page where it addresses free air resonance and presents a rather eyebrow raising anology. In the second paragraph of the "Natural Vibrations" section it talks about tethering the strings of a double bass violin to the body of the instrument.....and compares that condition to the spider and surround of available speakers. Do you think this could true?

TAD makes some excellent 15" woofers that have free air resonances in the mid-low 20s. They are also easy to drive: 8 ohms and 97 db.

One characteristic that I have become accustomed to is the natural low end roll off that all speakers have, usually around 40hz, why is that?? Do the spider and surround cause this? This company is claiming their driver to have a flat response beyond 10hz, and their driver has no spider or surround. Apparently this was in a large enclosure,"approaching an infinite baffle". Further reading shows a roll off when the new driver is in a 5 cubic foot box. Even with that roll off their tests show it to be 16db more efficient than the 18" driver they used. If their claims are true then the bass reproduction that this driver is capable of must be incredibly sweet???

TAD makes some excellent 15" woofers that have free air resonances in the mid-low 20s.

They sure do! TAD are among the very best.

How do the latest field coil woofers, like those used in some Shindo speakers, compare?