Eminent Technology LFT-8b in Harry's system


I recently signed up for the V.P.I. Industries newsletter, and today received my first such. In it, Harry Weisfeld reviews a Grado phono cartridge, but this post concerns one of the speakers he listed as being those he uses to listen to music and evaluate recordings through. All but one are traditional dynamic cones/domes in a box designs, only one being a planar/dipole. That planar is the Eminent Technology LFT-8b. I'm pretty sure Harry could, if he so chose, have instead as his sole planar a pair of $6000 Magneplanar MG 3.7i's, or even $14,000 20.7's. But nope, he instead chose the $2500 ET LFT-8b, imo the greatest value in a loudspeaker on the market. I compared it to the 1.7i, and the difference was dramatic.
128x128bdp24

Good point about the LFT-8b maintaining it's resolution at lower level/volume. It's more like an ESL than a magnetic-planar in that regard. That Maggies need to be cranked to a certain level to fully "open up" is widely acknowledged, being somewhat veiled and opaque at low levels. That is another reason the LFT-8 is better for a smaller room than are the Maggies. I love Maggies too (my first high end speaker was the original Tympani-I, and I now own a pair of Tympani-IV's and IVa's), but they really need a bigger room than does the LFT-8b.

The fact that the LFT-8 has been in production for twenty-five years, and has had only two revisions---a change of the woofer and the tweeter, both retrofitable to the first LFT-8 ever made, and at nominal cost---speaks to the "correctness" of it's design. The recent Magnepan "i" revision can not be performed on the 1.7, which must be a real drag to owners of that fine speaker.

The LFT-8's magnetic-planar midrange driver, which as has already been stated covers the frequency range of 180Hz to 10kHz (without a x/o, the entire midrange and all but the top octave reproduced by a single driver!), has remained unchanged in all that time. As has the x/o and woofer box. The m-p driver and ribbon tweeter are bolted onto a metal frame, while the Maggie drivers are glued onto an MDF frame, which exhibits some flex and resonance, hence the need for the Mye stands. Big difference!

All the LFT-8 needs is the revolutionary Eminent Technology TRW-17 Rotary Woofer. Unlike the LFT-8, however, it ain't cheap! 

bdp24, Really 120 db at 0 Hz?  The sound of silence.

The LFTs are somewhat like my Beveridge panels in their principle of operation, except the Bevs work on high voltages provided by the Beveridge amplifier, rather than on electromagnetic forces. (Unlike a classic ESL, the Bev mylar diaphragm is low impedance because its coated with aluminum; the amp drives both stators and the mylar. There is no static bias voltage on the Bev diaphragm.)

Ha! Hyperbole on my part Lew, obviously. But close to it (let's say 120dB @ 1Hz ;-), the Rotary Woofer not being constrained by physical excursion like mechanical transducers. A really fascinating, revolutionary, visionary creation from the mind of the brilliant Bruce Thigpen.

You have Beveridges, Lew? Another visionary product, with direct-drive amps for the ESL drivers designed by Roger Modjeski of Music Reference. I'm green with envy!

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Well not to hijack the thread but this has me thinking. Anyone have experience pairing the LFT-8b with low power SET amps like my Art Audio Jota? The Jota is famous for being able to power relatively inefficient speakers (something to do with its big output trannies), and the LFT-8b's appear to work well with lower watt amps (my HC Jota puts out 24 tops I believe). But maybe this is asking too much? As it happens the same 2.5k could buy me upgraded wiring in my speakers (Devore Silverbacks), or a new set of LFT-8b's.