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.
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Great speakers for many years and they don't get enough attention by us Aphiles, 

Harry does  have a good ear.

As does ET’s Bruce Thigpen! His TRW-17 Rotary Woofer is the product of a very creative and talented designer, unlike anything else in the field of audio engineering. Brilliant, I tells ya! There’s a guy over on the Planar Speaker Asylum who augments his Martin-Logan ELS speakers with Magneplanar Tympani-IV bass panels as woofers, with the TRW-17 as a sub. Now THAT’s a full-range system---flat to 0 Hz, at 120dB!
I bought a pair of Eminent Technology LFT-8B speakers last December.  Fantastic sound and a great price.  I actually chose them over Sonus Farber after a demo.  I was prepared to drop $16K or so and was happy to realize it was not required to get great sound.

My preamp is a McIntosh C2300, amp is McIntosh MC402.  ALso have a REL sub.  Great sound.  
Nice system tubular1! Well done. 
I seem to recall a comment from HW somewhere on the intertubes in which he expressed amazement at the fact that Eminent could offer the LFT-8b for 2500$. A lot of value there - I'd like to try a pair some day.
They were recommended to me by the late Brooks Berdan. He included an evaluation of the design and theory behind Hi-Fi products when deciding what to sell in his shop, and was a long-time Eminent Technology Air-Bearing Arm dealer. He installed that unique arm on first the Oracle table, and later the VPI HW-19. Brooks found the push-pull design of the Eminent Technology Linear Field Transducer---the LFT (magnets on both sides of the LFT’s Mylar driver) inherently superior to the single-ended Magnepan magnetic-planar driver, and it’s vapor-deposited conductor superior to the Maggie wire conductors, being of far lower mass. They have superior low-level resolution and transparency (Maggies need to be cranked up pretty good to overcome the "Maggie mist"), as well as dynamics, and play better at low volume than do Maggies. They play louder with less power, too (regardless of the relative sensitivity specs), and have a more extended low end (except for the huge 20.7). But that Maggie ribbon tweeter is sure nice! I have both LFT's and Maggies (as well as Quads), but for $2500 it's no contest imo. Maybe if ET had more dealers, and/or got more reviews, the LFT-8b would have a higher profile. People don't know what they're missing!
bdp24, thank you.  That is the sort of response that can actually be of some value for anyone wondering about the ET speakers.  You included rationale as well as personal observations.
I'd love to try a pair, but I'm absolutely a bottom feeder, audio wise.  (Retired, on a fixed income).  There just aren't enough used ones out there.
If you’re in the northern Washington state area, there are a pair of LFT-8b available from Planar Speaker Asylum forum member "Davey". His asking price is only $1500, a ridiculous bargain.
After 12 years in my system, its the only component I haven’t upgraded. No urge to get rid of them. I am constantly amazed by the LFT8b’s as they do so many things well. Such a seem-less zero distorted spacial sound. Just got done listening to the latest Radiohead album and what a great experience it was. Highly Recommended!

I power them with a Primaluna Dialogue Premium Integrated. They don’t need a lot of power in my experience.
aniwolfe, why the ET's aren't as commonly owned or even discussed as are Maggies is a mystery to me. The 1.7i with the essential Mye stands cost more than does the LFT-8b with Sound Anchor stands, and are simply not as good a speaker (okay, imo). The ET's make the 1.7i sound "wispy", lacking tonal density and body. The ET's magnetic-planar driver covers 180Hz to 10kHz, without a crossover! The dynamic woofer goes lower than the 1.7, the speaker plays loud enough for R & R and Symphony Orchestra, and with less power required than the Maggie. The single highest value product I know of, and almost no one owns them. Weird!
You might also want to add the LFT8b’s sound much better than the 1.7 at lower listening levels as well.

You know I think Bruce is ok having a small company and being able to provide great customer service. He makes upgrades to his products if he feels its substantial enough.

I have to admit I am happy he doesn’t come up with a new version of the LFT every few years. That would drive me crazy and it would turn me off.

I like how he came out with the new tweeter years ago and all his customers had to do was just replace it by unscrewing it. No soldering involved...easy! That tweeter upgrade really made a huge difference.

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. 
I really don't want to rain on anyone's parade but like every speaker I have tried, the LFT-8B have a few flaws and they can be quite intrusive.  I had them paired to my Belles 150a amp.  The bass from the woofer was never quite right in my room.  Way to under-damped and boomy.  The other issue was the panel itself.  They are supposed to be crossed over at 180 Hz but I wished that wasn't the case because at moderate volume, with bass heavy stuff (think Patricia Barber), the panel would distort, panel slap is what I have heard it called.  So, they are nice, very nice for classical but not up to the reference quality some people here claim.  I liked my Martin Logans I got after that a little more.
  
What? The LFT-8b’s aren’t perfect?! I like my Quads (original 57's) and Magneplanar Tympani-IV's more than the LFT's in some ways, but that's not the point of the post.
As I understand it, Roger Modjeski was definitely "around" Harold Beveridge, and if anything he may have had a hand in the design of the amplifiers or maybe just building them.  But Beveridge was the guiding genius behind the whole ensemble, and I do think his work merits the appellation, "genius".  Like the work of many other geniuses, his work had a few minor flaws, like a weak bass amplifier and under-specified woofers, for the 2SW model that I own.  His first loves were the models 1 and 2.  There apparently very few Model 1s ever made, and less than 200 pairs of Model 2s and 2SWs.  The 1s and 2s were full-range.  The 2SW goes down to 100 Hz, and below that you have to supply the woofer.  I use a pair of KEF B139 woofers in transmission lines that I built myself 40 years ago, externally powered by a Threshold 50W class A amp.  There were Models 3 and up, also, but all those speakers are conventional ESLs that require external amplification.

Nice Lew! I'm a fan of the B139 (Dave Wilson is too, using a pair in each WAMM, for mid-bass), and I have a pair of ESS TranStatic I's that use it in a quarter-wave (I think it's called) transmissionline. The  midrange is covered by a KEF B110 5" Bextrene cone, the highs by a trio of those great RTR ESL tweeters, the same ones Bob Fulton used in his Model J. I had a pair of those in '74, for about six months.

I'm dying to hear Modjeski's current Direct-Drive ESL speakers, powered by tube amps of his with no output transformers---the amps driving the ESL's directly (hence their name ;-).

First of all, what a coinkidink!  Back in around 1970, I was being paid very little as an intern in a hospital, and I craved a pair of IMF Monitor loudspeakers.  As a financial compromise, I bought a pair of IMF Studios, instead (from Lyric Hi-Fi in Manhattan).  The Monitor used a KEF B139 in a Bailey-type TL, a KEF B110 midrange, and a KEF tweeter.  Not entirely satisfied with the Studios, I eventually decided to try to build my own pair of Monitors from scratch.  I had a patient who agreed to let me use his table saw, and I acquired two 4X8 sheets of HDF, about 1.2 inches thick, and lots of clamps, glue, screws, etc. I bought the B139s and B110s easily enough, and then I found a guy in California willing to sell me RTR ESL tweeters (the blue rectangular ones), as many as I wanted, with a power supply to drive them.  I bought eight, with the intention of using four per speaker.  Thus I built a TL speaker with the B139s and B110s in entirely separate TLs. (The woofer cabinet is nearly a carbon copy of the Bailey design, a la the IMF Monitor.)  And the four RTR ESL tweeters were arranged in a linear array along one side of the woofer enclosure.  A few months later, I met an EE who helped me design the crossover and in fact wound me some inductors.  This was a darn good speaker that blew the pants off a pair of Magneplanar Tympani 1Us, when they came on the market.  I moved from this speaker to full range ESLs shortly thereafter ( 2 pairs of KLH 9s), and I sold the home-made speakers to my cousin, who used them for at least 20 years.  When he finally wanted to be rid of them, I bought them back, cut off the parts of the cabinets that supported the B110s and the tweeters, and stored the TL woofer cabinets in my basement for another 20 years.  Then I bought the Bev 2SWs and finally saw a use for the B139s in the TL. (I had kept a pair of NOS B139s, all that time.) I still use one of those B110s as a test load when I work on my amplifiers.  The B139 won't take much amplifier power, but I think that in a TL, it is one of the lowest distortion woofers ever made.

A tube amplifier with no output transformer is called an OTL.  OTLs can drive any speaker, other than an ESL, with a high enough input impedance.  What the Beveridge, the Modjeski, and other ESL "direct-drive" amplifiers do in addition is to drive an ESL with no step-up transformer at the ESL end of the chain.  So, no transformer in the signal path, at all. To do this, direct-drive amplifiers have to develop thousands of DC volts at their outputs; the audio signal rides on the high DC voltage, which simultaneously biases the ESL.  (The Bev speakers are a special case of an ESL where the diaphragm is low impedance; classic ESLs have a very high impedance on their diaphragms.) DD amps are OTL, but not all OTL amps can DD, is my point.

I know what an OTL is, ya big silly ;-). I had a pair of Atma-Sphere M60’s for years, which I bought for driving my old Quads. One cool thing about them is you can take out half the output tubes, to create a 30 watt version of the amp, perfect for the easily-overdriven Quads.

You’re right, an ESL speaker with a direct-drive tube amp has not only no output transformer in the amp, but no step-up transformer in the speaker, eliminating two sources of distortion. I know Modjeski’s current ESL speaker/D-D amp product is designed and built that way, as I believe the Beveridge was. I think it was to accomplish that that Mr. M was hired by Mr. B. I think they were both in the Santa Barbara area at that time, a beautiful city on the California/Pacific Ocean coast, just north of Los Angeles. Modjeski relocated to the San Francisco bay area a couple of years ago, where he runs Music Reference and teaches a course in amplifier design at a local adult education school. Wish I still lived in San Jose!

When I bought the TranStatics in ’81 (for $400, out of The Recycler, a weekly S. California paper), one of them had a generic oval woofer instead of a B139. I called ESS in Sacramento, and they had one, and only one, left. I paid all of 39 bucks for it! The B139 ESS used in the speaker wasn’t the standard version---not having the four "ears" through which mounting bolts pass---just a perfect oval. I first heard the speaker in ’71, but being a starving musician couldn’t come close to buying a pair. They retailed for $1200 in ’71, the Infinity Servo-Static $2000. Ten years later I was happy to find the TranStatics, and could now buy them. Still have 'em, but man are they heavy---140 lbs. apiece

bdp24, Sorry for the pedantic discourse on "OTL".  You would be surprised at the number of audiophiles who do not know the differences in meanings of the terms: OTL, balanced, push-pull, single-ended, and direct-drive.  My main point was, as you know, that your Atma-sphere amplifiers could not directly drive the screen of an ESL, but they are OTL.  However, once in a while, Ralph Karsten makes noises about building a direct-drive amplifier; I am sure he could do it.  I use a pair of MA240s to drive my Sound Lab speakers, in my "main" system.  Joe Curcio, I think, also claims to have a tube-based input circuit mod for the original Bev amplifiers.  The originals, like mine, use solid state input circuit, and yes yes yes, they are direct-drive.  (Bev speaker Models 1, 2, and 2SW are directly driven.)

No apology necessary Lew! To assume ignorance is not a bad idea ;-).

Modjeski’s new ESL is sold as an integrated speaker/direct-drive tube amp---no output transformer in the amp, no step-up transformer in the ESL. A stand-alone direct-drive amp is impossible, as a universal model/design can’t take into consideration the different nature/characteristics/needs of all the speakers it may be asked to drive. A direct-drive amp must be designed for a specific speaker, and for that speaker alone. I’ll bet the Beveridge was Roger’s first attempt at such a design, and I wonder how his new one differs from it. He did also design a "normal" OTL, the rights to which he sold to Counterpoint, who manufactured and marketed it as the SA-4.

Your KEF driver project was very advanced for a hobbiest, Lew. Transmissionlines are not easy to build, requiring a lot of knowledge of acoustical theory, speaker enclosure design, and cabinet building. I’m impressed!

A new review from Harry arrived today---HW Review #2 (07-03-2017). The subject of the review is the Modwright 150 Phono Section, but here a couple of quotes from the review regarding one of the speakers Harry listened to the Modwright through---yes, the Eminent Technology LFT-8b:

"A $2500 wonder."

"I typically find the ET's to have the best mid-range I have ever heard from any speaker."

The other speakers mentioned in the review are KEF Blade 2, JBL Everest, and Joseph Audio Pearl 3.

@ rotarius "I really don’t want to rain on anyone’s parade but like every speaker I have tried, the LFT-8B have a few flaws and they can be quite intrusive. I had them paired to my Belles 150a amp. The bass from the woofer was never quite right in my room. Way to under-damped and boomy. The other issue was the panel itself. They are supposed to be crossed over at 180 Hz but I wished that wasn’t the case because at moderate volume, with bass heavy stuff (think Patricia Barber), the panel would distort, panel slap is what I have heard it called. So, they are nice, very nice for classical but not up to the reference quality some people here claim. I liked my Martin Logans I got after that a little more."

Well, sorry to say that, but your Belles amp probably is not a good match for the LFT 8bs to say the least (some would say it is distinctly mediocre, but we all hear differently I guess) .... That is a first time I hear panel distortion of the LFT 8s, or the bass issue you have described, and I ve heard about dozen of ET 8bs and ET 6 installations. The room and improper placement is usually the culprit. Also people using jumper cables instead of true bi-wiring affects their sound to the worse. Did you tighten the panel with hex screw driver as per ET/or your dealer instructions? The tightening (but NOT OVER tightening) makes a HUGE difference in the overall sound quality of the LFT 8bs... If you like solid state amps you should try once in your lifetime to buy used Electron Kinetics EKSC 2a stereo amp and pair it with LFT 8bs...

I ve pretty much heard all Martin Logans ever since late 80s, and the only pair that would match or better the LFT 8s (not to mention the superior, sadly long discontinued model 6s) in overall coherency, wholesomeness , realistic timbres, the ability to portray recording venue with realistic proportion, the freedom from having to sit smack in the middle with once’s head firmly affixed in one position was that model that features wide panels plus woofer towers, a la Infinity IRS... and those were about 25 grand back in early 90s....

The only speakers in my (NON) humble experience that would match or exceed the LFT 8bs performance in spatial, tonal and dynamic nuance would be Apogee Divas, and Apogee FRs, and Eminents own 6s... in a very large room.... The LFT 8bs can be magical even in small to medium size rooms...

Being one of those obsessive music lovers that like to own as many different speakers as possible, I was considering the purchase of new Bowers Wilkins 802d3, or 800D3.... So I went, and I listened, and I listened, and I liked what I heard ALOT... Then I returned home and after hearing the same music on my ET 8bs even in my second, less than ideal, small listening room, I could hear that the most excellent B&W were NOT as fast, natural, delicate, open and spacious as the LFT panels.

.... There is an audiophile in princeton, nj that has ET 6s with the Nestorovic subs with two pairs of german Symphonic Line 4 monoblocks with separate crossovers in a spatial room.... I ve travelled far and wide all over the world for work, and was able to listen to systems at different audio shows, and to the million dollar systems in homes of Russian oligarchs, but none of those were organic enough, or able to match this Princeton Eminent Tech based system.... . Bruce Thigpen IS a genius!!!!!!

So, yes, in essence the Eminent Tech 8bs are reference speakers, for ALL the possible musical genre as my 20 000 albums collection can attest.... if you know what the properly recorded music sounds like ;)
As an FYI the Belles amp in question and his amplifiers in general are simply outstanding. Easily one of the most overlooked builders in all of high end audio. I owned the Ref150 as well as the 350.  Wonderful in every way. 
No doubt the Belles could be outstanding as well within carefully matched system ...

kot, I tried for quite a while to find a pair of the LFT-6’s, but never did. I had to settle for the LFT-4, which it's sort of a half-size version of the 6. It’s great for smaller rooms, as long as one has the usual distance from the wall behind the speaker than dipoles require---3’ minimum, 5’ better.

The LFT-8b is a great candidate for bi-amping (or at least bi-wiring), and ET makes it easy. There are two pair of binding posts on the top of the woofer box, one for the woofer and one for the magnetic-planar midrange & ribbon tweeter drivers. The x/o is 1st order (6dB/octave), so one can bi-amp passively---it’s cheap! Vertical bi-amping with identical amps helps with that, as their input sensitivities are matched. Or, a moderately powered tube amp can drive the panels, and a ss the woofer. The LFT has a nominal impedance of 8 ohms, but the panel itself is 11-12 ohms, great for tubes.

I second kot's recommendation of the Electron Kinetics Eagle 2A, one of which I own. A great, great amp for bass in particular. I haven't heard the updated/modified version kot cites, but even the original is fantastic, a real classic.

I was told by my ET dealer that LFT 8bs while a relatively easy load can dip as low as 3 ohms at certain frequencies, that is why Electron Kinetics and Symphonic Line are such a good match with them.... Having said that I ve driven mine 8bs with AudioPrism (red Rose model 1) Debut 1 (35-40 of kt-77 watts per channel), quite nicely but in a relatively small room. Also have been using Rega Mira 3 integrated in the summer in the very same room as well with great results.. A year ago a fellow audiophile here in NY was offering Cello Duet 350 for sale, and we brought that amp over and moved the 8bs into my much larger living room to see how the combo would match.... Those 350 watts of Cello, man oh man, just grabbed the 8b with iron fist and refinement I seldom heard .... Too bad I could not physically accommodate the Cello in my room for permanent placement (domestic issues and all), but the result was musical neutrally redefined, and as neutral to the source (I used DAC straight into into Cello with adapters, using digital volume control on my MAC) as I had ever heard.... And that Cello can be gotten for about 4 grand these days.... Just make sure to use a true bi wire or shotgun Cardas Golden Cross speaker cables as the new Clear Beyond series we also tried did impart too much of an analytical signature .... In any event, it was an amazing combo for a larger listening space!!!!!
@BDP24 If you REALLY want a fresh LFT 6, give Bruce Thigpen a call. If you ask him nicely (as I’m sure you would) ;) , he will produce you a one off custom pair of the LFT 6s, with all the improvements of the modern ET line and all... at a cost of about $9 grand... Bruce likes and enjoys interaction with audiophiles & music lovers  that appreciate and enjoy his work.... EVEN at the 9 grand price tag the LFT 6s are phenomenal, of course proper set up and larger room is a must to enjoy them in all their glory, but you know that better than I :)

Wish he would produce LFT 6 again on a commercial scale thou at a reduced price.... At 6 grand I would pull the trigger without blinking, even thou I lack the ideal conditions for them....Actually may be a bunch of us would band and pool orders so he might give us a lower price if lets say we order 10 pairs of the LFT 6... But, whom I am kidding....I know, I know it would be easier to have HIllary and the Donald to agree on something, than to have 10 obsessive compulsive audiophiles to agree to buy the same speakers at the same time , hahahaha ;)

Wow, a new pair of LFT-6’s! I’m gonna look into that.

Bruce includes a chart of the LFT-8’s impedance curve in both the owners manual and on the ET site, and the inductance of the dynamic woofer does cause an impedance dip. But the panels themselves have a very even, and for magnetic-planar and ribbon drivers, very high impedance characteristic, making them a good candidate for bi-amping and tube amplification, if that’s what one desires. Maggies, in contrast, present a 4 ohm and lower load to the amp, a real challenge for a tube design. The lifespan of tubes is greatly shortened when asked to drive low impedance loads, inefficient ones even more so.

Another point worth mentioning is that some consider the LFT-8’s dynamic woofer, though optimized for and blending well with the panels, to be the speaker’s weak point. If one desires more (or "better") bass output capability, the rather low 180Hz x/o frequency between panel and woofer allows one to use a sub of one’s choosing in it’s place. I am about to try just that with the bass panels of a pair of Magneplanar Tympani-IVa’s, an idea I became aware of recently on the Planar Speaker Asylum Forum.. Should be interesting