http://www.planotspeaker.com/index.html

I have read the How-it-works section, but don't have the knowledge to know if it's at all feasible.

One sign that it may not be pure woo is that he claims it'll be cheaper than current speaker designs, but the trail that led me to it went through 6moons, which kinda pegged the scepticism meter.

Will it work??

I didn't have the impression he's actually built one.

People have been coming up with all sorts of ways turning an electrical signal into acoustic energy for at least 100 years. Yet it's amazing how durable the basic coil/magnet/cone (or dome) design has proven to be. People tinker with the magnets, the cone material, the suspension, and the enclosure, but the basic theoretical principles of modern speakers are no different than what people were using in the 1960's. The only other technology that has ever made any inroads is electrostatic speakers, which have always had a tiny niche following since at least the 1950's.

Plenty of other technologies have come and gone (but mostly gone) over the years.

One other technology aside from electrostatic that has a foothold is the flat-panel speaker design (Distributed Mode Loudspeaker) patented and licensed by NXT plc, which uses a transducer (or several) to induce vibration modes in a flat panel. They also appear to have Balanced Mode Radiator designs that have good bass response and full treble in one unit and approximate an ideal point source radiator, so they say.

I'm not 100% convinced by talk of a universal sweet spot. Is it merely that there is a temporal spreading taking place, which might audibly affect the sharpness of transients and may lead to reduced precision in stereo location? I honestly don't know whether this occurs or whether the vibration modes superpose to make an ideal far-field in terms of timing or only in terms of phase for tonal signals, let alone whether this is psychoacoustically important.

They're a long way from having a foothold. It's an interesting technology, but it's not in wide enough distribution yet to see if it can survive as a practical and commercially-viable alternative niche to conventional speaker technology.

(is there anyone here on HA who owns one, and would care to comment on it?)

I am not sure of how the NXT transducers are even a real innovation. The NXT transducers I have seen were merely traditional dynamic voice coil motor assemblies, but with no diaphragm. The transducer simply vibrates whatever it's attached to. Basically, it acts like a tactile transducer, but in a wide audio bandwidth. This does not alleviate the specific problems inherent of any given radiation surface; these must still be addressed. "Distributed Mode Loudspeaker" appears to be marketing gibberish. Of course the system has 'distributed modes'. It can not possibly excite a surface in unison to act as a piston. If you want to see some examples of well engineered, hi-fidelity 'distributed mode loudspeakers' with purposefully engineered diaphragms, refer to Manger transducers, German Physiks DDD drivers, Airfoil transducers and Linaeum transducers.

-Chris

I'd like to see some specs on max. sound pressure and speaker efficiency.

Since the actual vibrating element seems to be designed rigidly and fixed with a given thickness - yielding to a comparably high mass, this speaker concept is likely to need high wattage for convenient loudness ... it doesn't seem to be that much of a "green machine" after all.

I like the broadband concept, though ... common crossover networks do have some nasty problems that cannot be easily worked around.

If I understood correctly sound wave is generated by "diaphragm" of triangular profile rotating back'n'forth. Not bad idea at first glance. I'm also sure that there is no working prototype still.

What "nasty problems that cannot be easily worked around" are you specifically referring to, in relation to known perceptual limits with music playback?

-Chris

From what I understand, the "Distributed Mode Loudspeaker" being discussed in this thread, is simply the device I specified in post #5. It has been available for a few years. It used to be sold at Target retail stores with fold out cardboard boxes that you attach them to use as 'speakers'. You could attach these full range vibration transducers to most any large flat and thin surface and get some sort of sound. Some retail products also used these NXT devices on essentially random flat panels internally and called them 'speakers'. Best Buy used to have some they were selling under their own Insignia brand name. The Audio Critic online magazine also measured some retail example similar to the Best Buy variant of this NXT technology.

-Chris

With "easily worked around" I am referring to inexpensive solutions.

Regarding my quote of "nasty problems" (might be an exaggeration) I am e.g. referring to:

- frequency response nonlinearities in the crossover area (especially problematic in the area around 2-4 kHz where your ear's sensitivity is highest and common tweeters start transmitting) - I know, these can be worked around with a proper choice of chassis with known low-tolerance TSP's and the according low-tolerance resistors, caps and coils - but testing for low tolerances makes speaker construction really expensive,

- lowpass coils with ferrite cores (these are smaller and cheaper than air coils but cause additional bass distortion and go along with stronger magnetic remnance/hysterisis ... that might be audible) or

- phase shifting that will make your amplifier sweat (or limit your choice of amplifiers) and degrades step response (which not every listener is susceptible to) ... these problems can be adressed by e.g. aligning the chassis' voice coils (the actual center of sound) in reference to each other which makes enclosure construction more complicated and expensive - good examples are the "Thiel" speakers.

I'm sorry, but "New Loudspeaker Design" being discussed in this thread and described in post #1 has nothing in common with "Distributed Mode Loudspeaker". The only similarity is plane surfaces of triangular diaphragm but they are not flexible at all as in NXT panels. The air wave is produced by rotation of the whole diaphragm back-and-forth in accordance with electrical signal from amplifier.

I've got two questions to the author of the idea:

1. What is the approximate width of diaphragm required for producing positive pressure at, say, 50Hz?
2. What's the purpose of homing magnets 38 and 40? Will they cause the equivalent of tensile forces of conventional speakers?

BTW, photos of prototypes' fragments appeared on the site yesterday.

Oh, please forgive my blunder. I somehow started from post 3's mention of the NXT technology. This new rotational driver is interesting, and definitely a rather new idea with promise.

-Chris

Actually, if this thing can deliver as claimed, it should potentially be able to [eventually] lower the cost of extremely high end level speakers. Omnipolar full range dispersion with extreme linearity, and virtually no resonances? To achieve this today requires immense costs, and still would probably not be able to match the potential performance that this new technology may accommodate.

-Chris

I'm pretty sure it will sound. But not sure the frequency response will be tolerable. What I would measure in the first place is static pressure at a distance, say, 1 meter and its dependence upon speed of rotation in one direction.

I do.

What i have is the logitech mm28. It's a portable speaker that sounds really good. I paid like 24 dollars at the moment, now they are at 16 on amazon.

On the amazon link there are many reviews. People seem to love them.

The short dimension of a face of the diaphragm could be 3/4" or 1."

the homing magnets are to center the diaphragm at its home or neutral position and also to return it to its home position. This performs some of the functions of a surround and spider of a traditional cone speaker driver but without their drawbacks.

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People have been coming up with all sorts of ways turning an electrical signal into acoustic energy for at least 100 years. Yet it's amazing how durable the basic coil/magnet/cone (or dome) design has proven to be. People tinker with the magnets, the cone material, the suspension, and the enclosure, but the basic theoretical principles of modern speakers are no different than what people were using in the 1960's. The only other technology that has ever made any inroads is electrostatic speakers, which have always had a tiny niche following since at least the 1950's.

Plenty of other technologies have come and gone (but mostly gone) over the years.

http://en.wikipedia.org/wiki/Loudspeaker

There are the planar magnetic speakers like the Magnepans and also the true ribbon speakers which are a sub set of planar magnetic speakers, which are another type of dynamic speaker. There are the bending wave speakers like Mangar and Jordan and the Walsh driver which are all dynamic drivers. A similar technology is the defunct Linaeum driver which still lives in the Aero technology-it lives somewhere around the bending wave technology. The Distributed Mode Loudspeaker is represented by the NXT platform. There is the DuKane Ionovac speaker, and it's derivatives, which used excited plasma and which are apparently a commercial dead end. Then there is the Planot™ driver.

The Planot driver is a dynamic type and its diaphragm is closer to a planar in size but it is rigid like no other driver. The Planot is able to "get away" with a larger mass for two reasons; it rotates or pivots around its long axis and it does not have a traditional surround and spider. Since it is not only the diaphragm but also the "support system" that is rigid then there is not a problem holding in place a more massive diaphragm. The only design reason for the diaphragm to have a greater mass than traditional diaphragms is for greater rigidity. And it is greater rigidity of the diaphragm that is the key to greater accuracy. A floppy diaphragm and support can not be accurate unless they are operating under conditions that approach a state where the deficiencies of the basic design flaws of traditional cone speakers are ameliorated sufficiently. They are operating in their sweet spot. This would be a horn loaded system where the loading of the horn allows high levels of sound to be produced by a cone that is hardly moving and therefore operating in a very narrow sweet spot for a traditional dynamic driver. But oh what a great price to pay both in terms of economy of manufacture and acoustically in terms of coloration and dispersion. Planar magnetic speakers are very big and don't have surrounds as such but stretch like a very large drum head. This is no piston no matter how large the diaphragm is and it is driven unevenly across its surface. It is amazing that they sound as well as they do!

Another quality that differentiates the Planot is that its dispersion is near perfect for a loudspeaker. It functions as a line source in the vertical plane and as an omnidirectional in the horizontal plane. It is the width of the driver that controls dispersion and the height that contributes to its efficiency.

Efficiency is another important quality of the Planot driver. According to common wisdom it should produce almost no sound at all. Most all of the sound produced should be canceled due to phase cancelation. It is not canceled! I did not repeal the laws of physics I merely found a "special case" that the normal wisdom does not consider. I have created what I call the 3-D Diaphragm™. This is what differentiates the Planot diaphragm the most. Because of the geometry of the "cross section" of the diaphragm it is freed from the tyranny of phase cancelation as the flat diaphragm is not. The flat diaphragm must forever be subject to its rule. It is very difficult if not impossible to see this feet. Our visual system is programed with a fixed set of "physical laws" that acts as blinders for our perception. If you look _very_ carefully at a triangle or a square or an octagon rotate about its center against a fixed field with a regular grid for reference then the story will begin to stand out from the perceptual background noise. You will see that rotational movement against a gas under pressure is a special case. You will see that where one increment of one surface moves forward in one direction (vector) another increment of the same surface moves forward in a different direction (different vector). So where at first look a percentage of a surface is moving "forward" and the rest of the same surface is moving backward in actuality the whole surface moves forward.

In my writing I have referred to the Planot diaphragm as a Mobius surface , as far as air is concerned. A Mobius strip is a strip that is rotated at it center and then joined at its ends. You can draw a line along its length and that line ends up touching its beginning! It is as though it has one side. To the air the Planot driver has no back side and therefore no negative pressure is generated as is by the back side of a cone or planar diaphragm. It is that simple. But oh how hard, our prejudices die! It has been impossible to convince anyone by logic alone that the Planot diaphragm even works! When people have heard it they are amazed because it contradicts their thinking about how things work. These same people are perfectly comfortable with the concepts of Quantum Mechanics and high technology but they can't believe that a thin diaphragm rotating can generate sound. This incredulity, I believe, is because of a powerful visual bias rather than an intellectual bias.

More to come: the economics of the Planot driver, two and three way Planot driver systems, overcoming the resistance of the driver industry to change their ways and the juggernaut of modern change.

John J. Gaudreault

> I have read the How-it-works section, but don't have the knowledge to know if it's at all feasible.

I must confess to having stopped before this point although I did look at the diagram.

> One sign that it may not be pure woo is that he claims it'll be cheaper than current speaker designs,

A reasonable speaker is easy to make, costs a few dollars and is small. This will costs a lot more, is large and complex.

> Will it work?

It will make some form of noise by it will be quiet, distorted and with no bass. Consider how it (tries) to compress the air as it oscillates. At the centre of one of the faces there will be no component compressing the air but as you move out towards the edge there will be a growing small component. Unfortunately when the face on one side of an edge is acting to compress the air the face on the other is doing something close to the opposite and so the small acoustic output will largely cancel.

It does work. It works very well. When I have constructed a new prototype, whose sole purpose is to be submitted for formal review, then there will be several professional opinions outside of my small circle.

My Web site is intended to introduce the technology not to the public but to manufacturers. Believe me when I say that a manufacturer is not going to waste money on a new technology until it _is_ proven. And you as a consumer surely will not have an opportunity to spend money on a Planot -tm speaker until a manufacturer has invested a considerable amount of money.

Yes it could be produced relatively inexpensively. When it as a commercial product you can decide if it is the right product for you. I hope you get the chance.

I am not a manufacturer but the inventor. So enjoy the theory for now and I hope it will be a product you can enjoy in the near future. Note that more than one manufacturer has expressed interested based solely on the technology.

J.J.G.

> It does work. It works very well.

How? If you have built a prototype then you presumably know it works poorly as a loudspeaker or do you expect the next prototype to fix all the problems?

> When I have constructed a new prototype, whose sole purpose is to be submitted for formal review, then
> there will be several professional opinions outside of my small circle.

The OP said something about 6moons. You do understand what the 6moons site is? and what a glowing review on the site means?

> My Web site is intended to introduce the technology not to the public but to manufacturers.

What made me stop reading was your misuse/misunderstanding of technical terms. I suspect technical people from prospective manufacturers would do likewise. Marketing people might not though.

> Believe me when I say that a manufacturer is not going to waste money on a new technology until it _is_
> proven.

What new technology? A manufacturer will generally produce what can be sold and fits in with their other activities. Look at some of the devices on 6moons which I am sure you can see do not work and have not been proven other than by a glowing review.

> And you as a consumer surely will not have an opportunity to spend money on a Planot -tm speaker until a
> manufacturer has invested a considerable amount of money.

I look forward to seeing one with interest but I have my doubts about whether I would buy one as a consumer.

> Yes it could be produced relatively inexpensively. When it as a commercial product you can decide if it is
> the right product for you. I hope you get the chance.

I look forward to it.

> I am not a manufacturer but the inventor. So enjoy the theory for now and I hope it will be a product you
> can enjoy in the near future. Note that more than one manufacturer has expressed interested based solely
> on the technology.

Technology?

You have not responded to my simple technical explanation of why it does not work well as a loudspeaker with any technical argument as someone genuinely interested in the technology would. You have simply asserted it works well and gone off on a sales pitch. You have piqued my interest about what you are doing.