Steve Guttenberg finally reviews the Eminent Technology LFT-8b loudspeaker.

There is now an LFT-8c. It has a new woofer and a price jump to $4800 pair.

First off, this is the speaker value of the century. It is a Line Source Dipole (for the most part) with a force over area drive. All points of the diaphragm are controlled by the signal unlike regular dynamic speakers. It creates way less room interaction than a regular dynamic speaker.  It will create a much more life like image. The width of the drivers was properly chosen to create even horizontal dispersion. It's transient response is excellent. 

Like every loudspeaker out there, it is not perfect. When you stand up the high frequencies disappear as soon as your head gets above the tweeter. The vast majority of us listen seated so it is a quasi problem. But, the same thing happens if you are on the floor having fun with the wife listening to Sade.

The woofer is not a line source. It is a point source radiator. It is going to loose acoustic power with distance much faster than the rest of the speaker which is line source. Consequently, the balance is going to be right only at one distance. For most rooms this is a trivial problem because you can not get that far away from the speaker. The driver is actually a subwoofer driver and is capable of very long excursions vibrating the heck out of the rest of the speaker. The woofer set up was a compromise ET had to make to keep the price down and the morphology of the speaker more acceptable to most people. You have to be able to sell speakers. Ideally there should be four subwoofers spread across the front wall creating a line source and isolating the rest of the speaker from direct involvement with the woofer driver. 

As suggested by ET I would definitely biamp this speaker. It is not very efficient and two lower powered amps are probably less expensive than one very high powered one. You also get to lose an analog crossover that is probably limiting efficiency to some extent.

Mr Guttenberg has not heard 8 foot ESLs with a line source subwoofer array. But, that speaker system costs $100,000.  The ET  LFT 8c is accessible to just about all audiophiles at a very reasonable price. I hate the tonearm but I love the speakers!

@ieales , As a former Tympany user myself just what are you doing now? The system you described above? 

@ledoux1238: I myself am opposed to the proposition of subjecting the output of analogue sources (phono, reel-to-reel and cassette tapes, FM tuner) to digital conversion, so won’t be getting the 18LS.

However, for those wanting one of the other advances of the LFT-8c and upcoming 18LS---that of dipole woofers in place of the 8b’s monopole woofer, there is another route available: just use separate dipole woofers, leaving the LFT-8’s woofer disconnected.

A dipole woofer system has been in development at Magnepan for quite a while now, and is reportedly about to be introduced (price not yet known). And then there is the Rythmik Audio/GR Research OB/Dipole Sub, which is two or three (your choice) 12" free-air woofers installed in an open baffle "frame" (@ricevs mounted them on a flat open baffle---3 layers of MDF!), the woofers powered by a servo-feedback plate amp. The plate amp controls include those for phase/time-alignment for woofer/loudspeaker mating, and of course output level (again for mating with the speaker), x/o frequency and slope, 1-band EQ, etc,., but accomplishes those jobs electronically, not digitally. It’s a great bass system, but is available only as a kit. You can get a CNC-cut flat pack that is a breeze to build (just wood glue and clamps, finishing of your choice) from a Canadian woodworker connected with GRR, and he will even build and finish the frames if you pay him.

And if you have the room, you can use the two bass panels of the Magnepan Tympani’s as woofers for the LFT-8b. They won’t play as low as the OB/Dipole Sub, but with enough power (and bracing) will get down to the low-30’s. Harry Pearson’s favorite bass reproducers!

@mijostyn 

As a former Tympany user myself just what are you doing now? The system you described above? 

Yes

Harry Pearson’s favorite bass reproducers!

I thought the Tympany were OK at the very bottom, not great. BUT, at the time I owned them, I was a recording engineer. Perhaps my perspective was colored by the awesome low end in some control rooms. OTOH, the Maggies' midrange and top were sublime.

Properly setup and configured in a good room, the LFT-8b, as I mentioned to Bruce, are "Merciless on bad material and sublime on well recorded."

@bdp24 I convert everything to 24/192 and RIAA correct the phono stage in the digital realm. I use digital crossovers, EQ and room correction to amazing effect. You have no idea what you are missing. But, I understand the purist approach. I drive an old 911. I have own new ones and do not like them, too darn refined. 

@ieales , You are not imagining anything. The bass of the Tymps is flabby at best. In total I think the 20.7 is a better loudspeaker. It still has less than optimal bass.

You are 90% of the way there with your speakers. IMHO your next move should be to disconnect the woofers in the speakers and build four 10 or 12" passive  subwoofers and space them evenly out on the front wall flanking the ETs. I would drive them with two amps and keep the channels separate, not mono. The crossover point I believe is 180 Hz. If you use a steeper slope (10th order) with your digital crossover you can safely push the crossover point down to 160 Hz. Time align everything and your bass energy will simulate a live performance. I use my old JC1s for subwoofer duty but I use to use a pair of QSC  commercial AB amps to great effect. Much less expensive. Dayton and Parts Express make incredible subwoofer kits at great prices. You can build for 12" subs for less than the cost of some commercial 12" units. Their drivers are absolutely top notch. I use 8 of their 12" Reference HO DVC drivers in my new subs. Each enclosure gets two drivers. I will be publishing the photo history of their construction on Imgur shortly.