Gilmore Audio planars revealed


The Gilmore Audio speaker have finally been photographed for the world to see: Gilmore Audio

Disclaimer - I'm a dealer for the Gilmores, though at this point I'm still awaiting my first pair, as they haven't begun shipping yet.

The Gilmores push the edge of the envelope for planar technology in several areas. Innovations include an extremely thin (3 mil) Kapton diaphragm; bass extension to below 20 Hz; easy 8-ohm load combined with 92 dB efficiency (you can drive 'em with Atma-Sphere M-60's!); and maximum output level in the mid to upper 120's.

Designer Mark Gilmore is the webmaster of the Atma-Sphere Owner's Group website, as well as of the Sound Lab Owner's Group site. He's been around for a while, but this is his first commercial loudspeaker design (to the best of my knowledge).

I haven't heard 'em yet so can't comment on the sound (I know, that's all that really matters after all). I'm expecting a pair before the end of the year, and will post comments then.

Duke
audiokinesis
Duke,
This loudspeaker looks very promising. Most planar owners crave the dynamics of conventional drivers and most box owners crave the clarity of the planars. Maybe Gilmore has come up with the best of both worlds.
Color me skeptical but when I see that 60" ribbon floating I'll believe it is indeed lighter than air. Sometimes marketing statements turn me off regardless of the merits of the product being offered.
I'll buy-em if they come "with" the beautiful godess standing at the lower page, it's worth a long stare, wow !!
Speakers are cool though.
What appeared in the photos as a possible "center channel" with those long legs and two huge "woofers" looked pretty good to me! I'd definitely go for a 30-day trial period with her!

Oh,back to the speakers. What speakers?! Oh yeah, those things on each side of the model. They looked pretty cool too. Could be great, could be another "product of the month". 17Hz is pretty low for an open back dipole radiator, don't you think?
I spoke with Gilmore extensively at HE2003 (I think we talked a combined 6 hours or so). He told me about these speakers, and I sort of just noddeb my head politely, heh heh.

Anyway, it is cool that these speakers have come to fruition. Gilmore made them sound UNREAL. 92db efficiency and able to play 120db or so... Planer speakers just do not do this sorta thing normally...

I am looking forward to hearing these speakers.

KF
Twl, I think you're absolutely "right" about the "center channel" I'd opt for the "90 day trial" if possible ?
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Looks like a modern version of the Carver Amazing speakers to me. But the Carvers were very inefficient and needed a lot of power to play loud. Genesis used the Carver ribbons in some of its larger models. From what I hear, the Carver ribbons had irregular response in the high treble and that's why they were crossed over to super tweeters in the Genesis designs.

Time will tell if this new version can fulfill the ambitious promises of its proponents. There is some growing competition in this market right now (ribbon hybrids) so hitting the right price points could also factor heavily into this eqation.

I'd like to see shots of some of the other finishes and that center channel could be dressed up/down a bit too, come to think of it...
Hi Duke, yes I agree with Tom. Pretty aggressive marketing but it does catch the eye....and the model is "something" also. But kidding aside the open back is a question, isn't it? Anyway...I am interested in hearing your comments on this speaker compared to the Soundlab M-1's. I figure by the time this speaker is introduced and the bugs are out I will have my toy car (just got a Miata) paid off!! Then we can take a serious look at both of these speakers. BTW, I would love to fax over to you the floor plan of my living/listening room to see if the space is compatible for the M-1's.
Reminds me of a computer manufacturer quite a few years ago, who photographed their product on a mountan top with a scantily-clad babe. This apperared in their magazine ads. However, there was another version of the photo, with limited distribution. Use your imagination.

The computer was not so hot, and the company is long gone.
HI,

I run Glacier Audio and let me address a few things.

First, Duke thank you for the heads up but I want to make sure that people understand that the ribbon is point 3 mil thick -- not 3 mil. This ribbon is not at all a Bohlender-Grabner element. It uses proprietary technology, has many enhancements and is Kapton based. The statement that has been made is that it is lighter than the air it moves -- it moves a lot of air and if you took the mass of that air, it would be heavier than the ribbon. The ribbon itself is not lighter than air (future versions may be).

In terms of there being nothing new here, I must respectfully disagree. Everything is new. Mark will be the first to admit that he is indebted to Carver's past efforts for inspiration. But the following performance numbers are real -- they don't happen because of magic -- they happen because of good engineering and a lot of thought and analysis and experimentation by the creator, Mark Gilmore, who is one of the most knowledgeable guys in audio that I know of.

For model 2 --
Freq response: 17HZ to 26 KHZ
Compresses at 127dB (dynamic range)
Corian panel is essentially resonant free in audio frequencies
Linkwitz-Riley Crossover using highest quality components including air-core inductors (for lowest DC resistance possible) and non-polar capacitors.
92 db efficient.
woofers are hybrid planars -- they are flat-faced like planars with a topology that matches the ribbon for exceptional coherence (a first) with the ability to move in and out like a dynamic speaker and thus move tons of air -- thus bass with great authority -- and clean!
Being a dipole cuts down on the efficiency -- if the speaker were in a box, it would be at least 3dB more efficient, probably more like 6db -- but there is nothing like a well constructed planar dipole for emulating the real musical experience. And having dipole bass helps reduce standing waves since there is averaging which occurs from reflections.

As I mentioned in AudioAsylum, I am a proud owner and dealer of soundlabs (I have M1's. Rennaisance 4's and MB1's). Roger West's M1's when paired with Ralph Karsten's MA-2's (and signature magnan speaker cables by the way) changed my life. (that's why I sell them). The Gilmore speakers are the first that rival the electrostats for transparency, purity, coherence, elegance, delicacy, while delivering what up until today electrostats have had difficulty doing -- bass with authority, dynamic range and lack of resonance (although the U1's largely solve this problem). SO one of the readers has expressed exactly the promise that these speakers fulfill -- the wonderful mids and highs of the electrostats coupled with the commanding bass of dynamics. But the GIlmore bass has a coherence that I have never heard from any dynamics.

I hope that you will find this information useful.

Thanks
I am supposed to be the Texas dealer. I have avoided making comments until I hear them, which could be as soon as the end of October.

Guess my taste is different, the girl is not my “dream” female.
They showed a front view, and then a side view, I eagerly scrolled down for a rear view and was appropriately disappointed:(. I'd like to see the back side of the speaker too:).
Caveat emptor, center channels like that can be very high maintenance. Sure looks like it's worth a try though.
Sellerwithintegrity,

Please, rethink your remark about some speaker manufacturer making ribbons that are lighter than air. It isn't going to happen. Here's some reading for you:

May 7, 2002 - A new version of aerogel, the particle-collecting substance on NASA's Stardust spacecraft, has been recognized by Guinness World Records as the solid with the lowest density.

Dr. Steven Jones of NASA's Jet Propulsion Laboratory, Pasadena, Calif., a materials scientist who created the aerogel used by Stardust, also created a lighter version that weighs only 3 milligrams per cubic centimeter (.00011 pounds per cubic inch.) The team received the official certificate yesterday.

Guinness World Records approved the new aerogel's application for the least dense solid in March. Astronomer David Hawksett, Guinness World Records' science and technology judge, decided that Jones' aerogel beat out the previous record holder, an aerogel that weighed 5 milligrams per cubic centimeter (.00018 pounds per cubic inch.)

Aerogel is pure silicon dioxide and sand, just as is glass, but aerogel is a thousand times less dense than glass because it is 99.8 percent air. It is prepared like gelatin by mixing a liquid silicon compound and a fast-evaporating liquid solvent, forming a gel that is then dried in an instrument similar to a pressure cooker. The mixture thickens, and then careful heating and depressurizing produce a glassy sponge of silicon.

What remains is sometimes called "solid smoke," for its cloudy translucent color and super-light weight. Surprisingly, this seemingly brittle substance is durable and easily survives launch and space environments.

"It's probably not possible to make aerogel any lighter than this because then it wouldn't gel," Jones said. "The molecules of silicon wouldn't connect. And it's not possible to make it lighter than the density of air, 1.2 milligrams per cubic centimeter (.00004 pounds per cubic inch), because aerogel is filled with air." To change the density, Jones simply changes the amount of silicon in the initial mixture.

Stardust will use aerogel to capture particles from comet Wild 2 in 2004. NASA used aerogel for thermal insulation on the Mars Pathfinder mission. It will also be used on the 2003 Mars Exploration Rover, and may aid a proposed fundamental-physics testing mission and the Mars Scout Program.

Those may be mighty fine speakers but...
Lugnut...What if the aerogel were made with helium in it instead of air? Maybe we will need speaker hold-down cables instead of cones!
Interesting looking speaker, but what does the statement "compresses at 127dB (dynamic range)" mean? Are you really saying the speaker will output at 127dB? At what frequency? With what input? At what distance? Frankly, it doesn't sound plausible.
Eldartford,

Yeah, but better yet, let's use Hydrogen. Seriously, here's the explaination:

"It's probably not possible to make aerogel any lighter than this because then it wouldn't gel," Jones said. "The molecules of silicon wouldn't connect. And it's not possible to make it lighter than the density of air, 1.2 milligrams per cubic centimeter (.00004 pounds per cubic inch), because aerogel is filled with air." To change the density, Jones simply changes the amount of silicon in the initial mixture.

Plus, I don't think the aerogel would make a good ribbon.

Anyway, I look forward to the day when speaker cables are also used as tie downs. Again, these may be great speakers but this claim is so outrageous that it cannot go unchallenged. Heavens, if they could develop such a material, the last engineering use for it would be in audio.
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This is not a sensitivity measurement. I am sorry that you are having difficulty believing this claim, but very simply it is true -- compression has to do with when, despite the fact that you are adding power, the speaker doesn't get any louder. This "compression point" on the Gilmore AUdio speakers is 127dB.
Neat stuff. We'll see what the future brings. Roger West's M1's membrane is .1 mil (point one mil) thick. A very reasonable target to shoot for. But you do agree that the membrane can be lighter than the total mass of the air it moves. You agree with this, correct? Also, it would take a lot of helium to get those 180 lb a piece Model 2's to liftoff.
OK how much do they cost (L&Rs, I KNOW how much the center channel goes for and I can't afford it...the divorce that is ;~).
Sellerwithintegrity,

No, I don't agree with your lame conclusion. By that same logic your furnace is lighter than air too. Read your first post where you state that this particular ribbon isn't actually lighter than air but the next one will be. High end audio is filled with this type of marketing hype. Call it what you want but to me it's snake oil sales tactics. Again, these may be great speakers (we'll see) but this is an over the top claim which promises to bring snickers from anyone with a small amount of scientific knowledge. My guess is that you'll get beat up pretty badly in your own showroom if you stick with this pitch.
But you do agree that the membrane can be lighter than the total mass of the air it moves.

A confusing statement. In a longitudinal wave (such as a sound wave), molecules of "air" are displaced from a median position by varying amounts producing regions of compression (as the membrane moves forward) and rarefaction (as the membrane moves backwards) along the axis of propagation. The molecules end up where they started once the wave has passed. The wave moves - the air does not.

The very basis of a wave is the transmission of energy without the transport of matter.

I agree that it is desirable to have a membrane with as low a mass as possible without sacrificing stiffness. The thickness achieved in the design you are referring to is amazing.

Regards,
A 2 ton jet is lighter than the air it displaces too. Otherwise could'nt get off the ground.
Sellerwithintegrity, your answer to my question is somewhat evasive. Are you saying that the speaker can produce a 127dB signal level from 17Hz all the way up to the speaker's upper frequency limits at the recommended seating distance? Is there absolutely no output compression until 127dB is reached? And yes, it is hard to believe that a sixty inch ribbon (the width is unspecified, but doesn't appear to be more than 2 inches wide) can produce a 127dB output level. It will be interesting to see if any independent sources can verify you bold claims. BTW, 127dB is about as loud as jet takeoff on the runway. It's really, really LOUD!
Man, who keeps changing the laws of physics around here?! Only Congress can do that! Well, maybe the UN can, too, but they don't wanna.
There will be additional pictures on the website before the day is over, including a rear view.
You seem like a smart guy. Let me say a few things.

You need to lighten up a little bit. "We'll see what the future brings" comment was meant partially tongue in cheek but also out of respect for future technologies that will take a very different approach to sound reproduction. Of course membranes themselves will never be lighter than air -- you can just look at the periodic chart to figure that one out. But in fact, the claim that we are making, which Soundlab essentially makes also as well as other respected manufacturers that use ultra light membrane technologies, is that our membrance is very light and that that fact is important -- because lightness improves responsiveness and reduces distortion. SO this is a critical issue and the fact is that most drivers are relatively very heavy and don't move more air mass than their own mass. Ours do and that is significant This is hardly snake oil and hype. This is a critical distinction that can be measured. It is interesting to watch a small piece of our .3mil kapton membrane stay afloat for quite a while in a room, buffeted only by the normal air currents found in the home. In any case, we invite you to visit us at CES and THE-expo so you can see for yourself what we are talking about.

Thanks.
Yes, but it doesn't make a very good speaker membrane. It's not quite as responsive as .3mil Kapton.
Please bring your SPL meter to the CES and THE-expo to see for yourself. Sometimes paradigm changes are hard to accept. That is what we are looking at.
There are people who say that a solid state "watt" is different from a tube "watt". Maybe these are some different kind of dB.
FIrst, let me thank you for your kind words. But I need to respectfully disagree about the science you are espousing. Sound involves the actual movement of air molecules. It is not like light waves propogating in ether. It is the movement of air molecules due to pressure differentials that are created by sound waves -- the movement of molecules from areas of higher concentration to lower concentration.
Whoa, guys, we've got some real wacky science being bandied about here. FYI, movement of molecules from high concentration to low is diffusion, not sound. A jet stays up because of thrust and lift; a boat floats because the volume of water it displaces has more mass than the boat, itself. Have no idea how the speaker sounds, but would love to hear it and price it. Although I must point out that the WAF for the L&Rs is only a little bit lower than for the Center!!!!
Dear Sellerwithintegrity,
Sound involves the actual movement of air molecules.
The air molecules only vibrate. Each individual particle of the medium (air) is temporarily displaced and then returns to its original equilibrium position.

Waves can be divided into two categories: mechanical and electromagnetic. The very nature of this classification is that electromagnetic waves can propagate in a vacuum. You are correct that sound waves are not like light waves, although we lost the "ether" some time back ;-), but they are waves, and share some fundamental characteristics.

Another categorization of waves is into longitudinal waves (such as sound waves), transverse waves (where the disturbed particles vibrate perpendicular to the direction in which the waves move), and surface waves (where the particles undergo circular motion).

Let me give you another example of a wave to demonstrate that the individual particles don't in fact move. You are at a big football game, and the "wave" is started by the boisterous beer drinkers in section B. They jump up, hands in the air, and sit down. Observed by their neighbours, who at the right moment jump up ... and so it goes. Watching from the Goodyear blimp, we observe the wave travel around the stadium a few times until it dies out through boredom. But the lads in section B are still there. They didn't run around the stadium with their hands in the air, did they? No, they have to stay in the cheap seats.

Regards,
I don't understand why a lot you are gaining up on this new speaker. This is suppose to be a fun hobby with friendly people, what happened? Sure the speaker may turn out to be a dud but on the flip side it may be very special. Let's wait until we can hear them first hand and then give our opinion. Meanwhile I say hat't off for someone trying to improve our hobby.
I believe people have a healthy skepticism of a very expensive new speaker that makes rather outlandish claims yet appears to be no more than rehash of the Carver and a number of other ribbon/dynamic hybrids.

The manufacturer's dealers have posted on a number of sites touting these speakers, which makes them fair game for comment.

I suspect they sound very good, but wish they would go easy on the pseudo-science, cheap thrills advertising and exagerration.
Metralla- Each of the football fans in your analogy moved but they didn't get transported. This type of movement (call it a "wave" or "vibration") is the type I assume anyone in this hobby is refering to when they use the term "moves air". I think most understand that a speaker is not literally like a desk fan that blows air around.

What I thought was more interesting was the claim that the ribbon is lighter than the air it , is totally meaningless. To explain: If one can hear sound eminating from a speaker, the speaker is air. At 127 db, one could hear the speaker from a good couple of miles away. Even with minimal dispersion, the volume of the air within the couple of miles that is is fairly huge and would weigh, literally, tons. So, when Sellerwithintegrity says that the speaker "moves (vibrates, waves)tons of air", he is correct. That the ribbon weighs less than several tons is meaningless. Even the air in my listening room weighs a couple of ounces. I'd be curious for Sellerwithintegrity to define his terms.

The other interesting claim was that the ribbon is .3 mil thick. If memory serves, both Martin Logan and Magnepan (and probably all the other planar makers except Sound Lab) have been using that thickness for years. Nothing new or impressive there.

It seems that these speakers have merit, just got to get past the initial marketing smoke and mirrors!

BTW- Three others have asked before without response- what do these speakers cost????

Jim



I don't purport to be a scientist - or even technical for that matter - but I have a question about the claimed 127db output claim.

According to what I've heard people say on this site, for every 3db increase in output, it takes approximately double the amplification (wattage).

If this is correct, even with the claimed 92db efficiency, it would require approximately 2000 watts per channel at 8ohms to achieve 127db.

If this is peak, maybe I could see it...maybe. But 127db continuous output across the rated frequency response seems a bit unlikely.

Besides, wouldn't 127db result in hearing damage?

As for Sellerwithintegrity's request that you bring your SPL meter to CES - If you attempt to achieve 127db with innocent bystanders anywhere remotely close to your booth, be prepared for the impending lawsuits and negative public sentiment that will surely lead to the company's early demise.

Achieving 127db just for the sake of doing it reminds me of the old joke about why a dog licks his b@##s.

What's the point?
I agree with Seadogs1. This is a classy and respectful site where we all share common ground with respect for our love of music and high-end audio reproduction. It's fine to inquire about new technology and ask probing questions about manufacturer's claims, but let's do it in a way that encourages people to share their ideas not inhibit them. The last thing we want or need is to roast people like they do on Audio Asylum.

Cheers,
DB
The statement was not that the ribbons are lighter than air, rather that they are lighter than the air that they push. Big difference.
Hello Again,
If you don't mind, I will use this opportunity to repeat what I have said on another forum, which I hope will be helpful to all the participants.

Thought I would take a moment to shed some light on three subjects.

First, our 127dB compression claim.

1) If you put the power necessary into a traditional woofer and try to push it to 127db, it would probably blow-up long before it got there. But we don't have one driver -- we have four to share the power.

2) We actually used a set-up that could generate at least 4000 watts to test the speaker's compression point. We wore ear-plugs too. We used pulses because we didn't want to kill our neighbors, cause a brown out and also because we were trying to emulate musical peaks. Yes, running our drivers under several kwatts of power continuously would not be tolerated politely by the drivers. They couldn't survive that. But music is "dynamic" after all, hence the term "dynamic range".

3) At around 127dB and around 4000 Watts, compression was noted -- 1 watt = 91 dB; 10 watts = 101 dB; 100 watts = 111dB; 1000 watts = 121 db... you get the idea.

So our whole point again about making this claim is two-fold:
a) The speakers get to the threashold of pain long before they compress. So they will play loudly.
b) More importantly, they will handle dynamic peaks of MUSIC very nicely indeed (as sound reinforcement speakers do) and very cleanly (as top planar dipole speakers do), thus effectively emulating the live concert experience.

Second, and somewhat related is the skepticism concerning the ability of our woofers to move sufficient air to accomplish authoritative bass. Cone excursion of drivers on some of the sites referred to are as little as 6mm. We are able to attain big excursions, cleanly -- plus or minus 2 inches! So our four woofers move a lot of air. To do this, "you can't use no ordinary woofer", as my grandmother would say. Not surprisingly, we haven't. It is a very unique, proprietary planar driver with a surround that allows it to function much like a dynamic speaker -- on steroids. The magnets and supporting structure are very robust. As a result, we have a woofer that is very responsive (it moves fast) while remaining very compliant (it tracks the wave form very nicely). It has a very high QTS. The four drivers share the load so they "run cool". Even reasonably high spl levels can be maintained without loss of performance. We think you'll like what we have done, unless your the jealous type.

Third, this is not a Carver facsimile. Again, Carver's Amazing speaker (second version in particular) served as a marvelous inspiration and we have tremendous respect and gratitude for what he has accomplished. We could replicate the Carver speaker for much less money. But then it wouldn't do what the Gilmore speaker can do or sound the same either. Essentially, when compared with the Carver Amazing, every component is different.

1) The panel is Corian and essentially non-resonant. Each wieghs about 80 pounds alone.
2) The ribbon membrane is 10 times thinner and has much different topology.
3) Woofers are very different as you can see.
4) Crossover is in another class altogether as we have described earlier.
5) Even the stand, that is made especially for us by Sound Anchor, is very special.

We don't agree that we are engaged in hype and hyperbole and that our goal is the elicitation of cheap thrills. We know that these speakers are expensive compared to most, but few speaker manufacturers aspire to the same aesthetic, even though they claim that they do . For those that do sincerely aspire to achieve greatness, we believe that our speakers represent an exceptional value relative to other top quality offerings. These speakers in our opinion represent a paradigm change -- that is perhaps why some of you find the claims hard to believe. Most of you are open-minded enough though to accept the possibility that what we have created may in fact be exceptional and we thank you for your graciousness. Those who know Mark Gilmore personally know that he is respected universally for his integrity, generosity, self-effacement and knowledge. We invite you all to visit us as CES and THE-expo. Along with that we ask one favor -- for those who have so far chosen to condemn publicly a product they have not heard and don't understand, I hope that you will be able at least to listen to the speakers with an open mind and in turn be as forthcoming with your praise if you feel that it is justified.

I hope that you have found this helpful.

HB
"Second, and somewhat related is the skepticism concerning the ability of our woofers to move sufficient air to accomplish authoritative bass. Cone excursion of drivers on some of the sites referred to are as little as 6mm. We are able to attain big excursions, cleanly -- plus or minus 2 inches! So our four woofers move a lot of air. To do this, "you can't use no ordinary woofer", as my grandmother would say. Not surprisingly, we haven't. It is a very unique, proprietary planar driver with a surround that allows it to function much like a dynamic speaker -- on steroids. The magnets and supporting structure are very robust. As a result, we have a woofer that is very responsive (it moves fast) while remaining very compliant (it tracks the wave form very nicely). It has a very high QTS. The four drivers share the load so they "run cool". Even reasonably high spl levels can be maintained without loss of performance. We think you'll like what we have done, unless your the jealous type."

OK, so it is now 'reasonably high' SPL levels. And you are claiming +/- 2 inches of Xmax. Excellent and unusual.

However, someone way smarter than me suggested I look at the surround of the drivers and consider whether such a surround would physically allow the cone to go in and out by 1 inch each way. Obviously it doesn't.

The high qts is also a sign of a weak magnet, which can be seen from the shots of the rear and compared to a high Xmax driver like the Adire Tumult. But that doesn't matter since bass = displacement in most universes.

Even then there is still no way 4 12 inch dipole drivers will come close to the volume you are talking about.

Unless you would like to share what frequencies we are talking about.
the speakers sound interesting but some questions aren't answered.

the speakers are described as acting like a very tall line source. a 40 inch (model 3) or 60 inch (model 2) ribbon doesn't go anywhere near from floor to ceiling. you don't say anything about horizontal and vertical dispersion. tilting the speakers back looks like compensating for limited ribbon length and very little vertical dispersion. could be the model 3 can only be listened to sitting down because of vertical beaming. and how can four woofers in one row about a foot away from the ribbon be called a line source? the distance between them creates an acoustic timing anomaly that produces comb filter frequency response. someone asked about that, no reply. how about doppler distortion associated with such long excursions? funny that the photos show no binding posts or crossovers.

i guess the proof will be in the listening. is the center channel an available option?
I'm still perplex.
And we ARE a civilised group here, I've been around long enough to know -- but I think the speaker presentation took a wrong turn s/where, despite Sellerwithintegrity's kind efforts:

Steved and Planar make excellent points about Qts and comb filter effects... and so have others.

I just still fail to see the "revolution"...
Not to say that this speaker will not sound spectacular; I LOVE dipoles, anyway. So does Steved, by the way:)

From the info gleamed from Sellerwithintegrity's posts and the pictures, and with all due respect, this *looks* like (no more than) a good passive dipole construction with a wide-band line source , & a point source array for the lower freq. -- passed @ the limit of 2pi radiation of the baffle??

However and IMO there is a lot of merit in designing a dipole with passive equalisation...

Also, designing a top-notch dipole to a cost level, has merit too.

10mm of Xmax is very good; the choice of four (parallel?) woofs explains the compromise of small magnets (woofers with big magnets like, say, the Supravox 400: Xmax: 8mm/qts ~0,4 /magnet +1,5T, cost over $600 EACH -- not the stuff for commercial offerings).

As to how they manage to have 4 high Q woofs outputting "clear" and fast sound to integrate with the low mass magnet ribbon, is a secret probably hidden in the xover Sellerwithintegrity refers to.

There's merit in that too.

The baffle shape is a quarter "heart" (hearts are reputedly excellent for dipole operation -- but think of universal waf with a heart-shaped speaker!)
So, that has been carefully thought out too.

What about the high frequencies -- over 18kHz (they're useful too)? I think that the addition of a tweet on that baffle would create, at least, phase and/or gp delay complications and filtering/equalisation difficulties. Also it wouldn't look as good (and deafen the beautifully engineered centre channel).

As Sean once wrote, I have trouble making my posts brief...

But here it is. What's the bottom line (i.e. the caboodle) for the B&G-like ribbon, the four woofs, the filter and, most of all, the hours and toil that went into finalising the design???