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As he promised, Guttenberg reviews the Eminent Technology LFT-8c.

 

Back in June I initiated a thread bringing to your attention the LFT-8b loudspeaker from Eminent Technology, and the review of it by Steve Guttenberg. In that review Steve mentioned he would be getting the LFT option of a new woofer section, this one being of dipole design (the 8b woofer is a sealed monopole), the new model designated as the LFT-8c. Below is a link to Steve’s new review of it.

The LFT-8b remains available at a price of $3200 (including shipping within the States), the new LFT-8c selling for $4500 shipped. The 8c woofer system includes a power amp for the front-firing 8" and rear-firing 6.5" woofers, and DSP for planar-magnetic panel/woofer integration.

Not mentioned in this new review is that Guttenberg greatly preferred the LFT-8b to not only the Magnepan MG1.7i, but also the MG3.7i, which retails for almost three times the price of the ET. Steve found the 8c to be even better than the 8b, the dipole woofer blending with the LFT planar-magnetic panels better than did the 8b’s monopole woofer (Magnepan themselves is still working on their upcoming dipole woofer system).

However, he found the 8c woofer to be good down to only 40Hz or so. Hey, 8" and 6.5" woofers can do only so much! And he didn’t like the sound of the DSP when engaged. The $1300 price-differential between the 8b and 8c may be justified, but there is another option:

Any dipole woofer system can be used in place of the 8b’s monopole woofer, it needn’t be the 8c system. A great alternative is the OB/Dipole Sub offered by Rythmik Audio in collaboration with GR Research. This woofer system consists of two (or three, your choice) 12" woofers mounted in a dipole "frame", powered by a Rythmik Audio plate amp (which also contains a dipole-cancellation compensation circuit). The only catch is that the woofer system is offered only in kit form, the user being required to mount the woofers in the frame. GR Research offers just such a frame in both DIY flatpack form and assembled (and even finished, if you wish). This woofer system offers bass reproduction of the bottom octave, with the same superior integration with the m-p panels as that of the 8c’s dipole woofer. The Rythmik Audio plate amp includes all the controls necessary for optimum blending of the panels to woofers, including a continuously-variable 0-180 phase control.

The combined price of the LFT-8b and Rythmik/GRR dipole wooer is still far below that of the MG3.7i, and imo is an outrageous bargain in today’s high end world of loudspeakers. Steve once again mentions he doesn’t like electrostatic loudspeakers, but finds the sound of the LFT-8b and 8c to match ESL’s in transparency, while beating them in dynamics and tonal density.

 

https://youtu.be/R4vC3V00-3Y

 

128x128bdp24
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bdp24's avatar
bdp24 OP
9,451 posts
 

The now-deleted post was from @vonhelmholtz, asking "Are you a dealer, or a representative of ET?" No offense taken, that’s a fair question.

The answer is nope, just a very satisfied ET LFT-8b owner, doing what I can to help reward the outstanding work of ET designer Bruce Thigpen, and direct magnetic-planar loudspeaker fans to what I consider the best value in that type design.

I’ve owned three pair of Maggies, one currently (Tympani T-IVa), and very well understand their appeal and widespread popularity. But imo the LFT-8 is THE magnetic-planar loudspeaker to own.

I am also a past owner of a pair of Infinity RS-1b, and imo the LFT-8 also bests that loudspeaker. The LFT-8 is good enough to have made me retire my Quad ESL’s, which was for many years my loudspeaker of choice, weaknesses and all.

I would still love a pair of SoundLab ESL’s, or even a pair Sanders. But the LFT-8 will do quite well for now.😆

ledoux1238
276 posts
 

While Guttenberg's reviews of 8b and 8c are both positive, I feel he did not review the  8c quite as it was intended. He dismissed the DSP function of the speaker, saying it did not sound as good. However, the DSP is an integral part of the 8c. The entire signal chain goes through a A-D and D-A conversion, so that one is able to adjust the low pass level as well as time align the high pass signal. The speaker is preset with a -14.5db on the bass and a 0.6ms delay between the panel and the woofer. Both these functions allow the speakers to integrate better with the listening room, provide a much more coherent soundstage with better image depth and width, and a better integrated bass response. 

I know there are those who say they can hear a DSP in the signal chain and dislike it. Just like there are those who claim they can hear a step-up transformer in the vinyl signal chain and dislike it. But with the 8c, it is through the 'digitization' of the signal chain that certain sonic defects could be remedied. I just wished Steve could have made a little more effort in discussing the 8c with and without DSP. 

If it were an issue of more and better bass, than @bdp24 's comment on the Rythmik / GR Research open baffle sub-woofer must be a great solution. But even the Sanders system uses an integrated DSP solution to the design. I just wish the DSP design methodology could be discussed more insightfully. I asked Bruce about the use of DSP in an email. And he claimed that DSP technology has advanced so much  that he can use it to do things that were just impossible a decade before. And given the advancement, he felt that DSP is the lesser of two evils, the other being a passive  crossover design.  

bdp24's avatar
bdp24 OP
9,451 posts
 

Good points you raise @ledoux1238. I admit to having reservations about digitizing all signals passing through the DSP of the 8c (and the Sanders version of same). I accept the assertion that digital technology has improved to the point of it being as close to complete transparency as is much of analogue, but still, why do it if you don’t have to?

One thing to know is that the 0-180 degree phase control (which provides from zero to 16ms of delay), gain control, damping control (high/low/medium), extension filter (14Hz/20Hz/28HZ), and crossover frequency (up to 300Hz!) and slope (1st/2nd/4th order) controls (amongst others) included in the Rythmik Audio plate amp make possible the integration of the LFT-8 panels and OB/Dipole Sub just as well as does the DSP unit. In addition, the OB/Dipole Sub features Brian Ding’s Direct Servo Feedback control of the 12" woofers, which also provide full output down to slightly below 20Hz, over an octave lower than the LFT-8 b and c woofers.

At any rate, both the b and c version of the LFT-8 really deserve to be more widely known by audiophiles interested in planar-magnetic dipole loudspeakers. Why on Earth it took Guttenberg 33 years to get around to hearing them is what I would like to know! Everyone knows about Maggies, while the Eminent Technology LFT-8 remains virtually unknown. Bruce Thigpen may prefer to keep Eminent Technology at a manageable size, but sending a few pair of LFT-8c’s out for review by print mags may provide him with a better eventual retirement.😉

willywonka
189 posts
 

I remember going to a previous Axpona show where they did a demo of an unreleased speaker in the 6K range that sounded very good. Does anyone know that model number and when that is being released?

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