Bound For Sound Issue #171 - Since 1989
Bound for Sound is published monthly by The DeWulf Publishing Cartel, 108 E. Division Street, Kewanee, IIIinois 61443 USA. TEL 309.856.5515; FAX 309.853.3193; e-mail at firstname.lastname@example.org; website at boundforsound.com. Subscription price for 12 issues is$30to U.S. zipcodes, $33 Canada and Mexico; and $45 everywhere else in the known universe serviced by a local post. Multi-year discounts offered.
BFS Audio Report
Eminent Technology LFT-16 Planar Magnetic Hybrid
The LFT -16 Planar Magnetic Hybrid Loudspeaker by Eminent Technology, $950. 225 East Palmer St., Tallahassee, FL 32301 ph. 850/575-5655, email@example.com, www.eminent-tech.com
More known for his linear tracking air bearing tonearm designs, Bruce Thigpen has recently made a splash in the loudspeaker industry with his true DC to 30 Hz subwoofer ($12,900). Before the bass fan came along, Bruce had already designed and sent to market two loudspeakers, both based on his LFT (Linear Field Transducer) technology. For the uninitiated, the LFT midrange planar panel in this speaker has a radiating area of approximately 4" x 6.5". It fires fore and aft, and therefore can be called a true, push-pull dipole. The two inch ribbon tweeter only fires forward, and is less ambient for that reason. The woofer is a 6.5" hard poly driver in a low Q sealed enclosure.
The importance of the midrange planar in this design cannot be underestimated. It takes over for the cone woofer at 250 Hz, carrying the ball all the way up to 7,500 Hz. Not leaving a whole lot of work for the other two drivers to do, the sound of this speaker is basically that of the midrange planar. If your system is set up to optimize the sound of that remarkable driver, you have one heck of a system.
Tale of the tape. The LFT -16 measures21.5"x9. 75"x9. 75" (HWD) and weighs 23lbs. each. It has an 8 Ohm impedance and is 85dB efficient. Minimum suggested power is 25 wpc, although as you will see in the body of the evaluation, more power, such as 150 wpc is preferred. Maximum suggested power is 200 wpc. The speaker is bi-ampable and has tweeter level settings for OdB, -3dB and -6dB. The diaphragm of the midrange planar panel moves between magnets on the front and back of the driver chassis in a way that magnet field intensity remains constant upon the driver. The low mass Mylar diaphragm being driven along its entire surface area, using etched foil traces like those used on high quality circuit boards. Crossover slopes are first order. Bass response is -3dB at 45Hz and 20kHz.
Set-up. Since these are bookshelf monitors, stands are essential. Actually, putting these speakers on a bookshelf would be a crime as they need and flourish with adequate space behind them to breathe in the room. I ended up positioning the speaker 34" from the side walls, 66" from the back wall, sitting on a 22" stand. The 8 Ohm load is an easy one to drive, the only reactive driver being the woofer. The speaker is inefficient. I can attest to that. It was one of the few speakers around here able to get the "current" meter on the Pass X350.5 to wiggle on bass and midrange transients. However, its low efficiency does not mean that one can crank the volume and forget it. While using the 600 wpc, XLH M2000 mono amps, I let things get a little loud on Red Norvo's, Forward Look and snapped the left channel woofer pretty good on a bass transient. Sounding like someone just cracked a whip in the listening room, I winced and feared the worst when the 600wpc XLH unleashed its power on the diminutive 3-way. But, it was okay. Broken-in for sure after that monster transient, the speaker barely broke stride as it continued to play.
Alright, 600 wpc was a bit much, but the speaker loves power nonetheless. The 25 wpc suggested by the manufacturer as the minimum power required is optimistic, unless they are being used as headphones in a small room. A more realistic approach would be a minimum of 100 wpc, with 150 -350 being preferred. Yes, that's a lot of juice to provide, but these speakers will pay back the effort many times over; with the additional power they just light up the room with activity and life.
The amount of toe-in used is dependent upon a number variables. I ended up preferring the speakers pointed directly at me, regardless of how far I sat from them.
Break-in took some time. Initially, the speaker comes out of the box a little dull sounding and not terribly dynamic. But, with a hundred or so hours on them, the speaker started to open up and my appreciation for them became greater and greater with each succeeding hour. Eventually, I came not to miss some of the excellent speakers that preceded them in the Big Rig. Oh yeah, I missed the bass of the larger speakers, and I will go back to those other speakers eventually, but these little 3-ways are extremely satisfying and every bit the high end product one could want.
Sonics. It took some time to like the LFT's, but it was well worth the wait. Listening to this speaker and realizing exactly how good it was, I was forced to think back to some of the pedestal loudspeakers of the past for the purpose of figuring out where the ET stood when compared to the best. Four loudspeakers come to mind: The TSM from Merlin (now updated), The Silverline, the Crown Joule from Sci-Fi (now discontinued) and the Sapphire from ACI (now updated). Each one of those speakers had something very special about them, creating an indelible audio memory. As vivid as some of those audible memories are, however, I don't think I could reliably use them as a basis for a comparison to the LFT -16 today. For the purpose of full disclosure, Bobby at Merlin has offered to update the TSMs I purchased after their review in BFS so many years ago. It's my fault that I haven't, but I know someone with an updated pair (Marc Yun) and after I'm finished here maybe Marc would like to take a listen. Also, I have the new Silverline SR-17.5 here for audition, but that is yet to begin.
Once everything is set-up and broken-in, the first thing one notices with the ET's is an astounding sense of transparency. This is true transparency and not merely a false feeling of detail and resolution caused by an emphasized upper midrange. This is borne out by the absence of a background color to the soundstage. Some speakers bring out a blackness, that while seductive in many systems is actually the result of the obliteration of low level ambient information. Grays and beige backgrounds can also result in varying degrees. With the ET the air which surrounds the playback is that of the room you are listening in. Low level info such as the rear wall of the studio is laid over the acoustics of your room instead of being covered over. I see this aspect of the ET experience to be directly attributable to the planar magnetic midrange driver and its electrostatic like sound qualities.
Another sonic plus that I directly credit to the midrange driver is the stunning coherence from the upper bass to the stratosphere treble. A single driver is used from 250 Hz to 7,500 Hz; that's almost five octaves of crossoverless sonics in the area where no crossover is most appreciated by the ears and brain. Many speakers utilizing a 6.5" woofer literally take the driver to well over 250 Hz at low pass. Doing so shoves the crossover point well into the critical range of audibility and is usually a matter for concern. With the ET, the coherence of this single driver portrays the musical event as a picture with fewer wrinkles and folds than just about anything around. Viewmaster-like? Yes, in many ways, though more vivid and without the flat images. For example, listening to The Yes Album with the ET allowed me to hear and enjoy every element of that complex performance to its fullest, including the hidden nuance and textures of Steve Howe's amazing guitar leads and the soaring (and sometimes shrill) vocals of John Anderson. This isn't an example of form over musicality, but an example of heightened resolution bringing the listener closer to the recording.
Depth and dimension are a special asset of the LFT-16. A good planar will always throw a deepsoundstage. Listen to any Magneplanar and one will perceive depth of image well beyond the plane of the speakers themselves. With the Maggies that I've heard and owned something else happens to depth perception -image thinning. Density of image can easily suffer as it seems that a true dipole tends to throw such great depth and image that there's only so much image density to go around. Images oftentimes grow large, too large to maintain the solidarity of the illusion, and that's when the musical illusion starts to lose life. Though I sense some of this in the ET; it's next to nothing. Depth of image with this speaker is nothing short of superb. Images do not shed their density at the back of the stage and tones remain solid, meaning that you don't tend to hear through the images on the stage as much as you hear the images themselves, at least that's what your ears and eyes are telling you. The ET does not project fake depth or shadowy semblances extending to the back wall. The projections all the way to the back of the stage have a seeming substance to them with this speaker, and the focus to that substance is remarkable from left to right, front to back.
If the midrange planar errs in any one regard it would have to be some added tizz that comes to the fore with solid state electronics in the upper, upper midrange. Maybe it's an artifact of taking the driver all the way up to 7,500 Hz? It was subtly audible with all solid state amps; I couldn't hear it with the OK Signature or the SE250 mono hybrids from Monarchy.
Going to the Rite of Spring on the HDTT label really offered the ET an opportunity to strut its stuff. This speaker's strengths closely trace those musical qualities one finds in classical music ...and I'm not talking about classic rock. The purity and transparency found with the ET adds a new view to orchestra hall. Massed instrumentation tends to smear with many speakers, even if it's just a little bit. The fine focus and spaciousness that the ET is capable of opens up the classical repertoire in your record collection. String textures have gut and edge, but not too much. Instrumentation at the back of the stage is not overwhelmed by all that is in front of it; it's a case of resolution as delivered by a coherent sounding driver.
The ET doesn't artificially expand the width of the soundstage by diffusing it, or by drawing images to the speakers themselves. This speaker, with careful placement can disappear to a degree that few other speakers can; again, blame it on that crazy midrange driver.
I'm not wild about the woofer driver. While it does a good many things superbly and its melding with the midrange planar is done extremely well, there were times that its hard poly origins were audible. It was manifested in the form of a slick darkness in the bass that once the signal dipped into the 40's turned one note with a small bump. Actually, in some instances this aspect of the ET's performance added some "kick" to kick drums and stand up acoustic bass. It's also in this area where things could get a little carried away and then out of control when driven very hard. This part of the speakers performance did not detract from my enjoyment of music with it, but it did serve to warn me that I was pushing the speaker beyond its capabilities volume wise.
Conclusion. If you like open sound with large dynamic capabilities from a relatively small package, the LFT -16 is an able performer. It's soundstaging abilities, i.e., the ability to present audible pictures in space, is simply superb. One can do better sonically, but not at this price -no way.
I consider the ability to hear the original spacing of a recording to be very important, though not to the extent that tone quality, harmonics and dynamics suffer. After all, when has a device of singular ambitions been all that effective? For that very reason (the adherence to singular ambitions), I don't care for speakers from Thiel, Lowther, most horns and the like. Producing a product that does one thing extremely right means that it probably does a lot of things wrong. Musical enjoyment to me requires a balance of priorities wherein certain characteristics of the sound may be emphasized and focused on, though not to the detriment of all else. The midrange of the LFT -16 depicts depth and dimension as well as any, but it doesn't do so at the expense of tone quality, dynamics or image density. One might complain that bass response has been restricted, but considering the size of the driver and its enclosure, physics determine the ultimate bass qualities of the unit. ET has pinched off a little efficiency in favor of some bass extension and slam, but the tradeoffs are not extreme, and in all fairness, this is a room filling design with more bass than many will ever need.
The sound of the ET is indeed a picture of balance and superb value. Listen to it. It goes to the heart of the music in ways that music lovers can handily embrace. In many ways it is a very unique product.
Good Listening! MGD
Bound for Sound is published monthly by The DeWulf Publishing Cartel, 108 E. Division Street, Kewanee, IIIinois 61443 USA. TEL 309.856.5515; FAX 309.853.3193; e-mail at firstname.lastname@example.org; website at boundforsound.com. Subscription price for 12 issues is$30to U.S. zipcodes, $33 Canada and Mexico; and $45 everywhere else in the known universe serviced by a local post. Multi-year discounts offered. Reprints through January, 1989 are available. Not one word from Bound for Sound maybe reproduced on paper, electronically,or in Esperanto without first paying homage to the Publisher and doing various acts of yard work (painting, mowing, washing the car) about his home office.
Reproduced with permission from Issue #171 of Bound for Sound