Funny how one search leads to another line of interest... I turned up this concept for driver design:
http://www.geocities.jp/adsshp/indexE.html
It looks like a lot of effort has gone in to R&D. Its an interesting idea, if a bit demanding in the magnet department.
Ed
http://www.geocities.jp/adsshp/indexE.html
It looks like a lot of effort has gone in to R&D. Its an interesting idea, if a bit demanding in the magnet department.
Ed
Surely not....
Actually I was searching for ideas, prior examples etc, of cylindrical speakers - something away from the Walsh, or other designs with a conventional driver and an acoustic diffuser.
I have this notion, and it's only a notion, of something like a Magneplanar, except it is wrapped around a cylinder, and suitably dimensioned to overcome the directivity that my SMGa's panels exhibit.
I can already anticipate constructional difficulties in tensioning a diaphragm and applying voice wires in this geometry, but it might be possible.
It's also anticipated that the enclosed volume might be used (or not) as a means to modify the bass response, though I wonder what might be lost here, in comparison to the open baffle nature off the maggie panel. Either way, you'd still have a tranducer with the benign impedance curve and minimal amplifier interaction that is characteristic of the maggie.
Any thoughts?
Cheers,
Ed
Actually I was searching for ideas, prior examples etc, of cylindrical speakers - something away from the Walsh, or other designs with a conventional driver and an acoustic diffuser.
I have this notion, and it's only a notion, of something like a Magneplanar, except it is wrapped around a cylinder, and suitably dimensioned to overcome the directivity that my SMGa's panels exhibit.
I can already anticipate constructional difficulties in tensioning a diaphragm and applying voice wires in this geometry, but it might be possible.
It's also anticipated that the enclosed volume might be used (or not) as a means to modify the bass response, though I wonder what might be lost here, in comparison to the open baffle nature off the maggie panel. Either way, you'd still have a tranducer with the benign impedance curve and minimal amplifier interaction that is characteristic of the maggie.
Any thoughts?
Cheers,
Ed
Yeah, ........ I get your drift Ed.
I too am looking at different ways to reproduce music.
I have large 2 way AZZURA horns at home and even though it sounds magnificent, I somehow feel that not all the information recorded on C.D.'s is getting through.
I'm also suddenly(overnight) become sensitive to colorations and distortion(why I have changed from S.E.T's to MOSFET SOLID STATE).
The horns are probably adding coloration also but not as much as some others I have heard.
Seriously considering building a tall ribbon to go as low as possible without too much of a speed mismatch to the dynamic bass section(if that's at all possible). I don't wish to go down the ribbon bass panel or ESS route at present - too much hassle.
I'll keep researching. If you find anything let us know.
I too am looking at different ways to reproduce music.
I have large 2 way AZZURA horns at home and even though it sounds magnificent, I somehow feel that not all the information recorded on C.D.'s is getting through.
I'm also suddenly(overnight) become sensitive to colorations and distortion(why I have changed from S.E.T's to MOSFET SOLID STATE).
The horns are probably adding coloration also but not as much as some others I have heard.
Seriously considering building a tall ribbon to go as low as possible without too much of a speed mismatch to the dynamic bass section(if that's at all possible). I don't wish to go down the ribbon bass panel or ESS route at present - too much hassle.
I'll keep researching. If you find anything let us know.
P.S...........used to own some TIMPANI's and MG11's .......loved em.........should have kept them except the W.A.F. came in on it !😡
Bart Locanthi at Pioneer in the early 70's used a pair of cylinders as tweeter and supertweeter in the HPM-200. The things were made from a piezo-electric film and were roughly 3" and 1 1/2" in diameter respectively. I have never seen or heard of this type of material being used for mid/low frequencies, but it would be interesting to try. Anthony Gallo currently uses a version of this tweeter in several of his designs.
Anybody know what this film is called or how to procure some?
David
Anybody know what this film is called or how to procure some?
David
Flat Coil ...
Unfortunately, it looks like a single-ended electrostat, meaning it will not have the balanced forces acting in it that will cancel even harmonics ... And will suffer from inverse square law non-linearity ...
Unfortunately, it looks like a single-ended electrostat, meaning it will not have the balanced forces acting in it that will cancel even harmonics ... And will suffer from inverse square law non-linearity ...
Hi,
since its motor structure relys on magnetic forces, it should be rather seen as a ´coiled ribbon speaker´, instead of a single-ended ESL.
But as toroid says it will be quite nonlinear because the coil is placed within the highly nonlinear strayfield of the magnets.
jauu
Calvin
ps. besides, the negative claims about ESLs on the website are false.
since its motor structure relys on magnetic forces, it should be rather seen as a ´coiled ribbon speaker´, instead of a single-ended ESL.
But as toroid says it will be quite nonlinear because the coil is placed within the highly nonlinear strayfield of the magnets.
jauu
Calvin
ps. besides, the negative claims about ESLs on the website are false.
david yost said:
I think they used a PVF (poly vinylidene fluoride) film, which is "poled" by applying a strong electric field while it is solidfying.
This is a vague memory of reading some description of the Pioneer technology 30 years ago or so.
David:-
I noted the Gallo design already, designated CDT I believe. It seems to have a very good reputation. Tricky to DIY though, without access to the piezo film material and vacuum coating equipment.
torroid88
Good point about the non uniformity of the drive in the voice coil design, that could be a problem. It's a frequent criticism of some Magnepan designs, though I still love these speakers.
Ziggy:-
I got lucky, when I suggested the Maggies to "Mrs H" she went out and bought a second hand set from Craigslist as a birthday surprise, preferring them over conventional boxes! I'm a lucky man indeed. Then I got to learn how to rewire tired maggies.
On the subject of 360° dispersion I also recently saw this Elac driver:
http://www.elac.com/en/products/classic/4pi2tech.html
Interesting stuff.
Now I wish I had an unlimited supply of surplus magnets.
I noted the Gallo design already, designated CDT I believe. It seems to have a very good reputation. Tricky to DIY though, without access to the piezo film material and vacuum coating equipment.
torroid88
Good point about the non uniformity of the drive in the voice coil design, that could be a problem. It's a frequent criticism of some Magnepan designs, though I still love these speakers.
Ziggy:-
I got lucky, when I suggested the Maggies to "Mrs H" she went out and bought a second hand set from Craigslist as a birthday surprise, preferring them over conventional boxes! I'm a lucky man indeed. Then I got to learn how to rewire tired maggies.
On the subject of 360° dispersion I also recently saw this Elac driver:
http://www.elac.com/en/products/classic/4pi2tech.html
Interesting stuff.
Now I wish I had an unlimited supply of surplus magnets.
"Back in the day" it was possible to buy samples of piezoelectric PVDF (Kynar) from Pennwalt, if I remember correctly (this was in the mid-1980's---man I feel old all of a sudden...). The film came in a few different sizes, some of which would be appropriate for tweeters, and was already metallized. It was very easy to make put together a simple prototype. I haven't tried to obtain the material since that time, so I don't know if samples are still available or what they now cost. They couldn't have been exorbitant when I bought them in the 80's because I picked some up while living on a graduate student's stipend.
Few
Few
Guys, if you haven't already done so, see my thread on PIEZO NXT TYPE PANEL. There's some weird stuff happenning with your common motorola piezo elements.
david yost said:
Are you referring to the permanently magnetized electret film, used in microphones (must be nearly universal in cellphones and such gear) and at one time in headphones? It was a remarkable R&D development at Bell Labs when I was there in the late '60s.
Electrets seem to work fine in single-sided microphones - contrary to my understanding of Hunt's ESL theory (esp as related to non-linear forces. Why? And I never understood why electret technology didn't replace ESLs since it works so well in high quality mics. Why?
how about building a "magnepan" with 5 coils (or more) and connect them like the Philips array (forgot the name for it at the moment)
Hi,
the problem with electrets are rather low charge values, i.e low equivalent bias voltages and weight. This prevented them from usage in ESL-panels apart from very small ones like heaphones and mics.
Because of the need of several layers of material beeing sandwiched to form one electret-membrane the weight of such a membrane has always been higher than a typical ESL-diaphragm.
It would be very desirable for every ESL-builder if there were a electret-material which is as light as the typical 6µm-PET and holding a charge equivalent to 2-3kV of Bias. It would for example completely omit with the problem of arcing!
jauu
Calvin
the problem with electrets are rather low charge values, i.e low equivalent bias voltages and weight. This prevented them from usage in ESL-panels apart from very small ones like heaphones and mics.
Because of the need of several layers of material beeing sandwiched to form one electret-membrane the weight of such a membrane has always been higher than a typical ESL-diaphragm.
It would be very desirable for every ESL-builder if there were a electret-material which is as light as the typical 6µm-PET and holding a charge equivalent to 2-3kV of Bias. It would for example completely omit with the problem of arcing!
jauu
Calvin
Calvin said:
I am greatly in your debt for that explanation.
Sounds like a modest amount of R&D could open a road in that direction, eh.
Really big panels? Very thin films? Higher permanent electret charging? Bigger drive voltages?
Hi,
If we look at the working principle of a symmetrical ESL, than we see a constant charge of single polarity (monocharge) which is positioned in a time-dependant (homogenous) electrical field.
Maybe I´m completely wrong, but if You use a monocharge electret (which can be produced in either polarity, positive as well as negative) You only need to connect the audio signal to the stator plates. You would not need any connection to the (electret-) diaphragm. This is the similar situation as if the HV-supply is switched off. As long as there is charge on the diaphragm the membrane moves because of the forces imposed upon it of the changing electrical field between the stators. But since there is no galvanic connection between stator and diaphragm there should be no arcing, even in the case of the membrane touching a stator.
A electret material would be needed that allows the application of a very thin layer on a base-film (PET), because good electrets show inferior mechanical and temperature parameters. It surely takes more than modest R&D to develop such a material. Industry could use such a material for many applications and major companies are researching within this field for decades. I heard rumours that recent research found a material with high potential, but I´ve got no further informations yet.
jauu
Calvin
If we look at the working principle of a symmetrical ESL, than we see a constant charge of single polarity (monocharge) which is positioned in a time-dependant (homogenous) electrical field.
Maybe I´m completely wrong, but if You use a monocharge electret (which can be produced in either polarity, positive as well as negative) You only need to connect the audio signal to the stator plates. You would not need any connection to the (electret-) diaphragm. This is the similar situation as if the HV-supply is switched off. As long as there is charge on the diaphragm the membrane moves because of the forces imposed upon it of the changing electrical field between the stators. But since there is no galvanic connection between stator and diaphragm there should be no arcing, even in the case of the membrane touching a stator.
A electret material would be needed that allows the application of a very thin layer on a base-film (PET), because good electrets show inferior mechanical and temperature parameters. It surely takes more than modest R&D to develop such a material. Industry could use such a material for many applications and major companies are researching within this field for decades. I heard rumours that recent research found a material with high potential, but I´ve got no further informations yet.
jauu
Calvin
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