Further to post #8,050,
Here is the Google auto translation of Transverse Technology. It is patented, still searching for the patent. If anyone can find it, I'd be be happy to read it.
Here's one of the images,
Another image is in post #8,047, which was used in another patent.
If anyone can understand the science in this, I'd be quite glad to know the how and why.
Here is the Google auto translation of Transverse Technology. It is patented, still searching for the patent. If anyone can find it, I'd be be happy to read it.
Here's one of the images,
Another image is in post #8,047, which was used in another patent.
If anyone can understand the science in this, I'd be quite glad to know the how and why.
Please look at these references for DML used in WFS...
https://www.tectonicaudiolabs.com/w...search-of-the-DML-Loudspeakers-Properties.pdf
https://www.researchgate.net/public...WAVE_FIELD_SYNTHESIS_BASED_SOUND_REPRODUCTION
https://www.researchgate.net/public...ON_OF_WAVE-FIELD_SYNTHESIS_TO_VIDEOCONFERENCE
A critical review of bending wave loudspeaker technology and implementation Master’s Thesis in the Master’s programme in Sound and Vibration KUONAN LI
Distributed Mode Loudspeakers for Wave Field Synthesis Delft University of Technology April 2001 Wilfred van Rooijen
Google for "The distributed mode loudspeaker Chalmers university" you'll find several interesting papers too...
Hope this helps.
Thanks. I have most of those, except the Wilfred van Rooijen one. Hope it's written in English, or there's a translation. Atm, trying hard to catch on the transverse technology. Old grey cells are protesting, though. 🙂
So I snuck back in here after about a week away to see if things have changed and I see you are still making asinine statements such as this one, glass doesn't bend, give exact specifications for EPS to manufacturers, and on and on and on!
Why don't you do everyone who has been enjoying this forum for years a a favor and go away.... start your own thread called "The Truly True DML Build" or whatever. You are definitely on the wrong one here, can't you understand this. I can't tell if you are posting from a an elementary school or a loony bin.
Could you do us all this favor, please.
Thank you!
Had a quick look. Interesting conclusions. More or less matches what you said here, #8,048.
A few moments ago, I had been reading about another DIY project that became well known as revolutionary product for some time. If you go down half way the article, you'd notice it was a DIY project. Later, I got a link from someone of a 80s product by very large company. Also got another link to a 70s product from the same person.
The omni-directional power radiation in a DML will never deliver the same curve as single-point response measurement on a box. Panels will (should) radiate equal power at frequencies beyond Fc. Pistons cannot approach this even into half-space. This is why a single, on-axis panel measurement might appear inferior to a beamed pistonic, but the perceived sound will be completely different (generally a lot brighter and clearer.)
Secondly, imaging on panels is not dependent on panel dimensions or orientation. In a properly-damped panel, the higher frequencies will (should) decay such that imaging is maintained in exactly the same way that a tiny triangle at the back of a live orchestra can be aurally located close to a massive contra-bass. Pistonics really battle with this because of bad phase coherence between separated drivers and electronics, and the dreaded IMD/Doppler issues which are almost unavoidable.
But because of the modal behavior of panels, and the massively reduced membrane movement in a DML, this problem is significantly reduced. The imaging of a DML is closer to a "holographic" concept, where an image can be precieved from any position, than the spotlight effect of a piston or cone where the image disappears when off-beam. Any DML builder who has picked up a rattle problem anywhere on a panel will know that the aural "position" of the interference follows the position of the ear next to the panel, and not the location of the problem itself.
Other than that, distortion in a decent DML panel has been repeatedly shown to be at least as low as Pistonics, and often much better. This has also been my experience.
A comment to the russian patent.
It’s surprising to see a patent that, more or less, is the same Oliver Göbel patent filed in 2002. ”Akustische Vorrichtung”
https://patents.google.com/patent/DE10246792A1/ko.
The patent describes the goebel high end transducer that they are using in their current Products.
It’s a bending wave solution.
I have built a couple of speakers based on the Göbel patent.
The membrane is a sandwich of carbon fibre, balsa wood and carbon fibre. Membrane thickness is 2.3 mm (made up of 2 mm balsa and 0.15 mm carbon fibre times 2. I’m a using a tectonic exciter. The exciter is glued to the membrane and hold in place with a crossbeam.
The size of the membrane is roughly 200x250mm.
Frequency range is 300-20000.
They are fairly cheap and easy to build.
It’s surprising to see a patent that, more or less, is the same Oliver Göbel patent filed in 2002. ”Akustische Vorrichtung”
https://patents.google.com/patent/DE10246792A1/ko.
The patent describes the goebel high end transducer that they are using in their current Products.
It’s a bending wave solution.
I have built a couple of speakers based on the Göbel patent.
The membrane is a sandwich of carbon fibre, balsa wood and carbon fibre. Membrane thickness is 2.3 mm (made up of 2 mm balsa and 0.15 mm carbon fibre times 2. I’m a using a tectonic exciter. The exciter is glued to the membrane and hold in place with a crossbeam.
The size of the membrane is roughly 200x250mm.
Frequency range is 300-20000.
They are fairly cheap and easy to build.
@Sandasnickaren
Nice!
Tell us more about your speaker. Thanks!
Edit: I found it, https://patents.google.com/patent/DE10246792A1/en
Nice!
Tell us more about your speaker. Thanks!
Edit: I found it, https://patents.google.com/patent/DE10246792A1/en
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Some measurements done from 1m in a room. There are some room influences in these measurements even though they are windowed.
I have done some measurements outdoors, but I cant find them. The peek between 200 and 1000 is less pronounced in those.
see these as indicative.
I have done some measurements outdoors, but I cant find them. The peek between 200 and 1000 is less pronounced in those.
see these as indicative.
I'm more interested in how you made the sandwich, why you chose these dimensions, the point you placed the exciter, and why you chose that point, how the sandwich is fixed to the frame, why the frame is like that, why you added back damping and such like. Also, would like to know your subjective feeling of the sound you hear from the speakers. And, whether you use a subwoofer with them. Thanks.
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Probably a lot like this:
https://www.diyaudio.com/community/...s-as-a-full-range-speaker.272576/post-6924919
Great job. That's a pretty smooth response, and nice low distortion. Well done.
I'm also interested in your perimeter treatment. How is the panel attached to the frame?
Do you have a spectrogram (wavelet)?
Did you ever try without the edge cuts? Did you put any silicone or other treatment into the slits?
Once again, nice speaker!
Eric
The sandwich is made out of 2 x 100 mm balsa sheets glued together edge to edge.
I am using Textreme 80g/m2 for the carbon fibre skin.
The balsa and the carbon fibre skins are laminated with epoxy in a vacuum press. I’m using a vacuum press as already have one. I beleive one can use som flat boards and clamps to achieve the same result.
The design is more or less based on the göbel patent.
The size is 190x 250 mm.
The cuts on the panel edges is taken from the first göbel product.
The frame is angled 45 degrees to minimize diffraction.
The padding on the backside is also to reduce diffraction.
There is is a EPDM 8x15 mm rubber between the panel and frame to reduce reflection from the edge of the panel and to reduce vibration from the panel in to the frame.
The exciter is tectonic TEAX25C10-8/HS high power 20w. It’s placed according to the patent.
The exciter body is fixed to the frame. The reason for this is that I had problems with my first implementation. I heard increasing distorsion after some time and I also verified it with measurements. The reason for this was that the exciter body was hanging down. Which was easily verified by holding the exciter in the rigth position by hand. Thus the included support.
I am very pleased with sound!
It’s very transparent, Can play any type of music jazz, classical, metall, small groups, large groups, electronic with ease.
Can play very loud.
Imaging is excellent.
Needs support of a woofer.
I am using Textreme 80g/m2 for the carbon fibre skin.
The balsa and the carbon fibre skins are laminated with epoxy in a vacuum press. I’m using a vacuum press as already have one. I beleive one can use som flat boards and clamps to achieve the same result.
The design is more or less based on the göbel patent.
The size is 190x 250 mm.
The cuts on the panel edges is taken from the first göbel product.
The frame is angled 45 degrees to minimize diffraction.
The padding on the backside is also to reduce diffraction.
There is is a EPDM 8x15 mm rubber between the panel and frame to reduce reflection from the edge of the panel and to reduce vibration from the panel in to the frame.
The exciter is tectonic TEAX25C10-8/HS high power 20w. It’s placed according to the patent.
The exciter body is fixed to the frame. The reason for this is that I had problems with my first implementation. I heard increasing distorsion after some time and I also verified it with measurements. The reason for this was that the exciter body was hanging down. Which was easily verified by holding the exciter in the rigth position by hand. Thus the included support.
I am very pleased with sound!
It’s very transparent, Can play any type of music jazz, classical, metall, small groups, large groups, electronic with ease.
Can play very loud.
Imaging is excellent.
Needs support of a woofer.