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

 

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My friend has the Lii Audio silver 10s ($1200 the pair) and he says they measure and sound very flat (no lowther shout). You need to seriously burn these drivers in and you CANNOT listen to their binding posts.....remove the binding posts and hardwire your speaker wire to the voice coil wire....its like a completely different speaker.

Of course, the latest 8b would sound and measure way better than the original 8......but modding the heck out of them brings them to another whole level.

Here is another variety of what I described above about getting planar sound on the cheap.  You get a Minidsp Flex (analog version)......use a Fossi amp for the woofs and an Aegir or other inxpensive tube amp or class D amp (another $100 Fossi, for instance)......You use 2 12 inch Beyma 12BR70 woofs ($160 each) on an open baffle and above it you mount 4 Parts express $60 planar drivers in series parallel (woofs in parallel).  WE are talking 94db woofs and 94db line source here!!!  The mini dsp is the xover, the preamp and the DAC all in one.  With both 12 inch woofs being directly driven by an amp and with no inductors in series and with equalization, the bass would kill, (I mean slaughter) the ET speaker.  You cross over around 400 hz to the mini line array planars and you will have sound so good you would die.  You run your wires directly from the two amps to the drivers (voice coil wires on woofs).  The minidsp ($500), wood ($300), wire ($300), 4 woofs ($700) and 8 planars ($550) would be around.$2500 with shipping....plus whatever amps you want (you probably already have an amp for the highs.....some or you have another amp laying around for the bass.  I would lake this anyday over a stock 83db sensitive 8B.  Of course, as I mentioned above a fully tweaked 8b with open baffle bi-amped speaker would be probably better (better planars?).  Alternatively, you could use one 10 inch planar driver from Radian ($660 a pair).....these might be more transparent than the Parts express planars but probably have less horizontal dispersion and way less vertical dispersion.  (If you sit in one spot then the Radians might be the ticket).

@ricevs I'm sure that would be amazing if you were able to get the filters right in the mini DSP. 

Regarding Lii Audio I still wouldn't connect amp directly to driver without passive filter or DSP for baffle step correction...there is no getting around the rising response...having said that, some people love a rising response for the extra presence it brings...just not me.  

What do you mean "if you get the filters right"  Using a DSP is easy....a 10 year old can do it.  You decide what slope you want and what frequency (I would start with 400hz and 24db per octave with the mentioned drivers) and then you measure the speaker....you adjust the amp levels and equalize and time align.....can be done in an hour by anyone with a measurement mic and a brain.  Of course, you can play with different xover frequencies and slopes (and fine tune the tweeter delay...mostly by ear).  Always fun to play.  But hard?....no way.   

Which Lii driver did you have?  They are all different.  As I said, my friend measured his Silver 10 (burned in for hundreds of hours and wired directly to voice coil wire) and it measured flat and sounded that way.....measured way flatter than the spec measurement from Lii.

@ricevs Lii 15 

I don't really want to start an argument but a single driver design playing wideband with no filtering can't measure flat. I wish this wasn't a truth, but it is. 

Regarding DSP, I agree easy to play with.... 

There is another positive review of the LFT-8c’s by Jules Coleman on the March issue of Enjoy the Music.com. Coleman’ picked up the review speakers directly from Guttenberg’s loft! 
it’s a long review primarily on his listening impressions and less on the technical aspects, e.g. DSP settings..etc.