Reliability with these transducers would be a key issue with me. One would not want to experience burnout of these units in the longrun. These speakers remind me of the Heil Air Motion Transformers which had a tendency to burn out. If these burn out and you cannot get a replacement, your stuck with a nice speaker cabinet with a woofer that ends up in the garbage unless you are a carpenter that can build some kind of high end replacement to your woofer to cover that gaping hole.
Let There Be LET
One of the biggest problems faced by transducers of all types is the speed efficiency with which they convert mechanical to electrical energy and vice versa. This is especially challenging for relatively massive speaker drivers, which must overcome a lot of inertia—the tendency for objects to resist changes in their motion—and move in response to the electrical signals they are fed.
Another issue related to mass is frequency response. For example, a tweeter of low mass will generally have a higher top end than one with greater mass, because mass is typically reduced by making the diaphragm smaller and/or stiffer, which shifts its break-up mode higher in frequency.
The faster the driver can respond, the more accurately the attacks, or leading-edge transients, will be reproduced, which improves the perceived sound quality immensely. As a result, most speaker drivers use a diaphragm with as little mass as possible—the more mass, the more inertia—and a voice-coil motor with as much power as possible.
Still, getting any diaphragm to respond quickly isn't easy, so a To address these issues, a company called High Emotion Audio has taken a different approach with its new tweeter called the Leading Edge Transducer (LET). Instead of moving the entire diaphragm in and out, the voice coil vibrates one edge, inducing the waveform to propagate through the diaphragm's special plastic material, absorbing it at the other edge to prevent reflections within the material. (Actually, this concept isn't new—a similar tweeter from a company called Linaeum made a splash about 15 years ago, but it has been largely forgotten since then. High Emotion Audio bought the intellectual property rights for that technology and has spent the last 10 years refining it.)
The inertia that must be overcome in this process is far less This process is said to be far more efficient than conventional pistonic vibration, and the company claims that the voice-coil motor is more powerful than most. allowing the LET to reproduce attack transients much faster than conventional tweeters. In addition, the LET is extremely efficient—about 100dB/W/m—and In addition, the diaphragm's surface area is about five square inches (compared with less than one square inch for most tweeters), which, combined with its sensitivity of about 100dB/W/m, allows it to produce very high sound pressure levels with relatively little power. An analogy drawn by the company is cracking a whip—a small motion in the handle can create a loud pop once the waveform reaches the tip.
The first products using this technology are the Bella 5 and Bella 7 (pictured here), rectangular bookshelf speakers that combine two hemicylindrical LETs firing forward and two more firing backward with a proprietary pistonic midrange/bass driver and custom-designed crossover in an optimized, ported cabinet. The tweeter's voice coils are attached to the inner edges of the curved diaphragms, and the waveform propagates to the damped outer edges. Also available are similar models with pyramidal cabinets, the Pyra Bella 5 and Pyra Bella 7 (shown at the top of this blog). Both 5-series models, which have 5.25-inch cones, list for $4950/pair, while the 7-series models have 6.5-inch woofers for $5950/pair.
Among the alleged advantages of this design is an exceptionally wide dispersion—the company claims 120 degrees at 20kHz—and ruler-flat impedance at all frequencies, allowing the speakers to sound roughly the same being driven by many different amplifiers in a wide variety of rooms. Another claimed benefit is extreme clarity, allowing you to hear deeper into the music.
Even more important, the company claims to have clinical evidence from research conducted at Belmont and Vanderbilt Universities in Nashville, Tennessee, that the LET's super-fast transient response and other design factors affect the human limbic system—which regulates emotion—more than conventional speakers, resulting in a more deeply moving experience and a greater sense of realism. In fact, the company's ultimate goal is to approach the emotional impact of live performance, which has heretofore eluded virtually all electronic audio systems. Leveraging related research, High Emotion Audio is also working on software to make digital recordings sound more natural.
The Bella 7 has already made its way into some recording studios in Nashville, where the company is based, and the response has been uniform praise. Among the comments is that it "undresses" recordings, allowing engineers to more accurately evaluate their work. This may or may not be a good thing for consumers, depending on the quality of the recording, but the technology embodied in the LET is fascinating nonetheless.
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Comments
Submitted by Scott Wilkinson on October 24, 2009 - 12:47pm.
Adrian, I had totally forgotten about the Linaeum tweeter, but you are completely correct. In fact, HEA bought all the intellectual property regarding the Linaeum tweeter and refined it to produce the LET. I have added a parenthetical to that effect in the main text. Thanks for pointing this out!
Submitted by Scott Wilkinson on October 24, 2009 - 1:08pm.
Kelsci, I agree that reliability is an important issue, and these transducers haven't been around long enough to know for sure. But I suspect this won't be a problem with the LET as it was with the Heil AMT, which required a high-intensity magnetic field and operated on a different principle. And you're right, the Pyra Bella does bear a resemblance to the ESS AMT-1, the first speaker to use the Heil AMT.
Submitted by Noah Katz on October 24, 2009 - 2:25pm.
Sorry, but the "explanation" of how inertia affects loudspeaker operation is full of errors. I'm not going to take the time to correct it, as the internet audio fora are full of similar thoughts and corrections thereof by the more knowledgeable. BTW, the mfgr's statements are no better.
Submitted by Scott Wilkinson on October 24, 2009 - 5:26pm.
Noah, please provide at least one URL to a webpage that disputes what I wrote. I'll gladly accept a correction if I'm wrong, but I need convincing evidence before I'll issue a retraction. My degree in physics gives me a pretty strong foundation in this case, so I'm curious to see if anyone can convince me that I'm in error.
Submitted by Kelsci on October 25, 2009 - 12:09am.
Scott, you are right that this transducer does bear a striking resemblance to the Linaeum tweeters that were found some years back on a line of speakers carried by Radio Shack. I never owned a set of those speakers but those transducers did play well. I do not however have any info as to their reliability over the longterm.
Submitted by Scott Wilkinson on October 25, 2009 - 12:38pm.
Noah, you're the one who's challenging my statements, so it's up to you to prove your point. It's your homework, not mine. I will investigate the statement you made here, but it's not much to go on. One question: what do you mean by "Fs"? Is the "s" supposed to be a subscript? If so, what are you using the "s" to stand for? Or do you mean "frequencies" (plural)? I want to be very clear and precise in our interaction.
Submitted by Stephen on October 25, 2009 - 5:52pm.
My 4 LX5 Linaeums that I got for $99 a pair are still going strong as surrounds for 2 of them and kitchen speakers for the other two. They still have exceptional sound quality within their range and terrific imaging and get used every day. Same goes for the Linauem Extremes I have in the living room. Too bad Linauem never matched the quality of the tweeters in the midrange and bass. If they have added to the top end response with better materials and matched them with appropriate lower end drivers they should be great. I am glad to see someone revive these things and do something good with them, they are exceptional up to about 15 khz. and still not bad for the next 3 khz. (that is about everything for what I listen to).
Submitted by Johnny Mac on October 26, 2009 - 1:37am.
I have 4 Optimus Pro X77s and a center channel speaker with the Linaeum tweeters. I use them with 2 powered sub-woofers as my main speaker system for music & movies. These speakers are real gems and have, IMO, better sound quality than the LX5s which my son had. I've had the opportunity to listen to some very high end expensive speakers and when I got home and listened to my speakers there was no let down. With high quality source material they can be magical. It's good to see that this technology has been resurrected and improved and that other people will get to enjoy it. Hopefully the price will come down over time. I've had to replace the woofers in two of my speakers because the surrounds went bad but I believe those Linaeum tweeters are bullet proof.
Submitted by Carl V on October 27, 2009 - 7:58pm.
Lineum once out of Portalnd Oregon if I recall correctly had some inovative desgins. Toshiba used the tweeter for awhile. Of course Radio Shack used the design with limited success. Lineum made their own speakers. I'm partially with Noah. Scott your question regarding Fs is enlightening & your not knowing about Lineum is equally enlightening. I hate to sound snippy...but this is within your baliwick is it not? AMT tweeters & their deriviatives are still being utilized ...look into Mudorf.
Submitted by Scott Wilkinson on October 27, 2009 - 8:54pm.
First of all, I'm not an audiophile in any strict sense and have never claimed to be—in fact, I've talked specifically about not being an audiophile on Leo Laporte's nationally syndicated radio show, so no secret there. I haven't spent years obsessing over consumer audio equipment. However, I have worked as a pro-audio journalist and recording engineer for over 20 years, so I'm much more familiar with that market than I am with the audiophile market. (BTW, I do consider myself a videophile.) No one knows everything, including me, so I always appreciate learning from readers, and I correct any errors I can verify. (I'm working on a response to Noah now.) What I don't appreciate is the holier-than-thou attitude exhibited by some audiophiles. I would much prefer to share information in an open, friendly, non-judgmental manner than deal with such an attitude.
Submitted by Barry Willis on October 28, 2009 - 4:32pm.
Audiophiles are forever sniping at each other over things they only partially understand. "Open-minded audiophile" is one of the classic oxymorons, like "trustworthy salesman." Likewise, engineers -- as opposed to scientists -- tend to dismiss anything that doesn't fit their textbook understanding of the way the world works. As the only one commenting on this who's actually heard High Emotion Audio products -- twice at the engineering lab in Minneapolis, and several times in Nashville -- I can attest that they perform as claimed, even if the technical explanation for their performance is incomplete. Scott should be lauded for consistently seeking out fascinating topics, not raked over the coals for lacking audiophile credentials. The fact that he isn't a true-believer audiophile (of any variety) helps makes his writing informative and entertaining. There are plenty of online forums where audiophiles and engineers can argue until they have carpal-tunnel syndrome.
Submitted by Lyle K. Goodwin on November 5, 2009 - 9:21pm.
I hooked up my Radio Shack/RCA LX5 Pro's just to hear them again. I bought them years ago as a close-out just for the tweeters. The only mod I needed was to plug the ports with rubber stoppers. The Linaeums are still smooth and sweet, wonderful stuff. Cheers!
Submitted by Scott Wilkinson on November 8, 2009 - 10:06pm.
Dear readers, After doing considerable research and conferring with some well-respected speaker designers, I have come to the conclusion that Noah Katz is right and I was wrong in some of the statements I made in this blog entry. So I've updated the text above, striking out the errors and adding what I now believe to be correct information. (Of course, the company's claims are just that, and I've tried to clearly identify them as such in the text.) For a more detailed explanation of what I learned, see this entry: blog.ultimateavmag.com/ultimate-tech/my_mistake/ I regret promulgating false information, and I hope you'll forgive my human imperfection. Also, I hope this episode will encourage others to learn from their mistakes.
Submitted by YouKnowMyName-Look UpTheNumber on November 12, 2009 - 1:24am.
More Cozy Acclaim by Scott and Barry: http://www.highemotionaudio.com/acclaim Radio Shack speakers with tweeter were $100 but now they are $6000. So you got to take them seriously. Not! Otherwise one is left to ponder being taken to the cleaners. Btw, this engineer knows that a ported enclosure degrades transient response. Analysis: just another overpriced mini-monitor.
Submitted by DocX on April 10, 2010 - 11:29pm.
I have a pair of these monitors for more than a year now. There is an emotional response one can get when listening to live music. Conventional speakers fail as they are imperfect at many levels. Most of the speakers in the market cannot produce a square wave, meaning there is a lag time in response, or a slope in the rise time for transient, which the brain deciphers as a false call. This leads to confusion b/w hearing an impulse and recognition and hence listeners fatigue. If the impulse is not natural, meaning a natural sound had a near instantaneous rise time, it will not register. To add is the intensity of the response, which conventional 1" domes may not suffice. Alternate technologies: German Physiks DDD, Manger drivers, Plasma tweeters from acapella etc.
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