Planar Speaker Asylum: REVIEW: Eminent Technology LFT-VIIIA Speakers by jeffreybehr

Model:	LFT-VIIIA
Category:	Speakers
Suggested Retail Price:	$1500/pair w/o stands
Description:	Hybrid planar magnetic/dynamic speaker
Manufacturer URL:	Eminent Technology
Model Picture:	View

Review by jeffreybehr ( A ) on May 28, 2006 at 23:17:24
IP Address: 68.230.67.50

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for the LFT-VIIIA

I must first acknowledge Bruce Thigpen of Eminent Technology as one of the premium-quality people in this business. Bruce has helped in my quest for the perfect speaker and is aware of my modifications, most of which he reads about probably with a large smile on his face and several shakes of his head. He has also replaced, for reasonable fees, a couple MR drivers I ruined thru my ineptitude and clumsiness. "Strain relief? STRAIN RELIEF? We don't need no stinkin' strain reliefs!"
My musicroom is largish at about 3200 cubic feet and was redesigned decades ago with music in mind, with few parallel walls, few 90-degree corners, etc. See http://forum.audiogon.com/cgi-bin/fr.pl?vdone&1126390461&read&keyw&zzjeffrey s for more information.

I've added the baffles, substantially changed the crossovers, and actively biamped my 8s. Iâ€™ve removed all binding posts from the systems, hardwiring the six pieces of speakercable. I use Audioquestâ€™s Type 8 soldered to the bass drivers, HomeGrownâ€™s SC-16/Silver Lace soldered to the inductors and MR panels, and a pair of 20g. silver conductors in teflon airtubes soldered to the high-pass resistor/capacitor network. The MR's 2nd-order low-pass crossover point is at least an octave lower than stock and is composed of an Alpha-Core 2.7mH series inductor plus an 8.6μF SoniCap/AudioCap hybrid capacitor in shunt. The tweeter crossover is, first, a 33-Ohm Kiwame 5W resistor followed by a 0.9μF cap, a hybrid of 0.22 and 0.47 Cardas Golden Ratios and a 0.22 Mundorf Silver/Oil. Iâ€™ve added a switch for adding a 39-Ohm resistor in parallel to the 33; it adds 3 to 5dB of treble for dull recordings.
Compared with stock ET8s:
1. The system is much warmer sounding than the stock version. The baffles add as much as 5dB of lower-midrage/upper-bass energy, and that's quite audible. The speakers now retain the orchestra's power produced by French horns, tubas, cellos, bass fiddles, tympanies, etc. This energy was being produced by the MR drivers but was lost thru what is called wrap-around cancellation, wherein the front and back waves emitted by the dipole radiator cancel each other increasingly as the frequency lowers. These speakers are NOT 'neutral'; I think 'neutrally' balanced speakers sound thin. Those who treasure accuracy or flatness in this warnth region might call my my speakers 'thick'.
2. The MR is cleaner and more transparent due simply to my removal of the original highly-cost-compromised electrolytic cap acting as a hi-pass filter. I've suggested to Bruce that improving that cap is one option he should offer. (Note 1)
3. The MR-to-bass transition is even-less audible, due to increasing the MR drivers' output in the lower-MR/upper bass due to adding the baffles (note 2) and then moving the bass's hi-pass filter points down a bunch. Instead of a 180Hz (? 160Hz?) single-order lo-pass filter on the woofers, I'm using 3rd-order filters, one at 40Hz and one at 60Hz. (One corner of my room reinforces bass less.)
4. The quality of bass is increased due to active filtering and some bottom-octave boost available in the old Dahlquist DQLP-1 filter I use. I'm sure there are many currently available electronic crossovers that would do as well or better. The bass is better defined...it's textured. For instance, in the big bassdrum strokes in the Holst Planets and the Goldsmith discs I love so much (note 3), one can hear not just the fundamental of the drum (in the 40Hz third-octave) but also the distinct reverberation (in the 25Hz third-octave); they're not simply mushed together. Also the bass power-handling capacity is improved because of the much-lower filter points I use.
Flaws? None meaningful for me, but their 84dB insensitivity has 3 effects I can think of. First, they require plenty of amp power (note 4). Secondly, they're not great at dynamic shadings, micro or macro, but this is NOT a sonic priority for me. Thirdly, they're definitely limited in their overall maximum output. Those in love with stomach-pounding, ear-damaging SPLs will NOT be satisfied with these. My PEAK levels at the listening position are about 95dBA, which I think is not very loud (but my wife disagrees; good thing I have a separate musicroom).
My prior speakers were Quad 989s. I loved them driven by ASL Explorer 805 SETs, but eventually I became more aware of what I felt was their slight surplus of treble energy, and, more importantly I think, I couldnâ€™t tweak them--and I AM an incorrrigible tweak. Maybe the 8s are a little less coherent than the 989s, but the 8s more than make up for that with their positive qualities.
The 8s retail for $1730/pr. including the Sound Anchor stands. Even adding the costs of an electronic crossover AND a SS stereo amp, one could have less than $3K invested in them. THAT is QUITE a bargain; I know of no $3K speaker system that comes close.
Notes:
1. IMO removing this 'lytic cap is the one change that every ET8 owner should make--unless, of course, you're a headbanger. Even this often-tin-eared audiofool could readily hear the improvement in transparency...cleanliness.
2. Removing the high-pass filter from the MR driver does NOT lower the MRâ€™s crossover point. The filter cap is there apparently to prevent the MR driver from being overdriven by high-level bass frequencies; its 33Hz filter point is FAR below any audible output of the driver.
3. Adrian Boult conducting the LPO; EMI LP ASD 3649; CDs CDM 7 64748 2, also numbered 0777 7 64748 2 3 on the spine (discontinued) and 7243 5 67749 2 6. Both are coupled with the Enigma Variations, but I prefer the 1st as The Planets are 1st in sequence and I never listen to 'Enigma'. The bassdrum stroke is about 2 minutes into the 4th movement, Uranus. The Goldsmith is 'Film Music Excerpts...' on Telarc SACD, #SACD-60433. The bassdrum is highly audible throughout the disc; I especially love the 1st cut, from the 1st 'Star Trek' movie. This is my favorite SACD.
4. I'm using and loving Antique Sound Lab Hurricanes in triode for the MR/treble and 2 channels of an Outlaw 770 on the bass. I tried initially a pair of ASL 50-Watt SETs, but even their 16-Ohm taps driving the 10-Ohm panels didn't produce high-enough clean levels. I also tried Quicksilver V4s; they had enough power but seemed to lack the magic that I got with the ASL SETs and that I get plenty of from the 'Canes in triode. The 770 is a 7-channel solidstate amp designed for home-theater use and is rated at 200WPC into 8 Ohms and 300 into 4, all channels driven.

Product Weakness: Doesn't reproduce dynamic shadings well; won't output high levels--headbangers need not apply.
Product Strengths: Spaciousness of dipoles; warmth; transparency; coherency; bass power and definition--yes, from that pair of little-bitty 8" drivers.

Associated Equipment for this Review:
Amplifier:	Antique Sound Lab Hurricanes and Outlaw 770
Preamplifier (or None if Integrated):	Audio Refinements Pre 5 and (currently) a conrad-johnson MET1
Sources (CDP/Turntable):	Denon 2900 UDP and Toshiba DVD/CD player
Speakers:	Eminent Tech. LFT-8s
Cables/Interconnects:	HomeGrown Audio's SC-16/silver Lace and IC-4 IC with their silver RCAs; Audioquest NRG-2 powercords
Music Used (Genre/Selections):	Large-scale Classical and film; small-group jazz
Room Size (LxWxH):	19 x 21 x 6.5 - 12
Room Comments/Treatments:	Ceiling rises from 6.5' to 12'; walls not very parallel; not many 90-degree corners
Time Period/Length of Audition:	about a year
Other (Power Conditioner etc.):	Three dedicated 20-Amp AC lines; Quantum Products Symphony Power Line Conditioners, 2
Type of Audition/Review:	Product Owner

Product Weakness:	Doesn't reproduce dynamic shadings well; won't output high levels--headbangers need not apply.
Product Strengths:	Spaciousness of dipoles; warmth; transparency; coherency; bass power and definition--yes, from that pair of little-bitty 8" drivers.