How to construct a cube louver (Acoustat) - Page 5 - diyAudio
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Old 11th April 2010, 08:32 PM   #41
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Location: Calgary on the Bow
Nice work Jim. what diaphragm material are you planning to use on this panel? Regarding the idea of using a power supply to heat the wires enough to permit them to melt into the surface of the louvre, it's a good idea which has been suggested a number of times and is very interesting. I made small samples where I used a flat iron to attempt this with only limited success. Later I purchased a small auto battery trickle charger to use as a supply to directly heat the wires as you have suggested but I never got around to trying it out. I was concerned about how I was going to keep the stator wires even with one another and keep the embedding distance the same for all the wires. I had thought that a plate of glass with some weights could be used to push the wires evenly across the louvre down into place. My concern was that the tension on the wires would pull the wires unevenly into the louvre. This technique is only going to work for a very thin dielectric insulation wire such as wire wrap wire or magnet wire. If this were to be attempted with a stator wire such as was used by Acoustat the wire will simply melt its way down through the thick insulation of the wire itself. So you can see the problems that might cause with diaphragm to wire spacing.
I can tell you that water based Acrylic enamel bonds very well to Mylar but I think that this could be a heavy way to go. There are a number of application specific coatings available on line which will contribute less mass to the diaphragm. There is also the original Quad Nylon coating which has the longest proven life span and yields a surface resistance in the low Gig ohm range. Acoustats coating is not nearly resistive enough so a replacement is a good plan. Its great to see folks working on wire stator designs they are a great way to build ESL panels. Hope that you post more pics as they are a great inspiration to those who might be sitting the fence. Regards.
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Old 11th April 2010, 11:21 PM   #42
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Yes Moray..been there done that These panels are in use now. I am using .5 mil Mylar. I also have made several with HS65 and HS 80. One thing I have been experimenting with is HS nylon film. It has some advantages, but also some problems. It does not have the dimensional stability of polyester film and is somewhat hydroscopic. The coatings I use are typically soluble nylon and soap. I like to use soap because it works and can easily be undone. One thing with heating wire, it changes dimension upon heating thereby requiring spring or mass tensioning during the process. I tried the iron method before and apparently had a similar result to your experiment. The soluble Nylon I use is a Dupont product and I have 2 different formulas. I don't recall either at the moment, but I can get the p/n of each if you need it. I have been building stats since about 1970 and have tried many things. Most things turn out bad! You often don't see the problems associated with brainstorms until you try them. I am a big believer in the Jantzen method of stator design. (ie wires). I spoke a few times with J. Strickland and he came to the same conclusion.
Another way of sinking small wires into plastic may be to tension the wires and invert the panel into a thin pool of MEK. I have not tried this yet, but it may also have a downside. (besides fire or death do to inhalation)

On the Nylon HS. If you wish to experiment with this contact me by email and I can send you some. I have .5 mil and .2 mil if memory serves.

BTW your high density wire mesh is quite beautiful. Nice work!

I made a tank for anodizing aluminum perf a couple of years ago. It made very pretty stators! But, I am a wire stator fan.

The carbon black formula I refer to is to help those who wish to clone originals. I have no personal biases associated with it.

My idea with the wire heating would require a mass loaded cantilever/pulley system.
I will let you know how it works.

Later my friend,

Jim
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Old 12th April 2010, 02:20 AM   #43
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I notice from a cube count that the panel in your picture is about 9 5/8 inches wide. You said that you were using 0.5 mil thick film on these panels. Do you play hard and loud? Am wondering if you have had any stability problems with your diaphragms? The standard Acoustat panel is around 9 inches wide and uses HS65 and is on the borderline of stability. Most folks never have issues but the guys who like it loud and proud can collapse their diaphragms with the right combination of bass and level. A 0.5 mil "C" grade tensioned would probably be stable but the HS65 does not draw quite enough tension to stay stable over that width (if you play loud).
You got me Jim I had no idea that DuPont made a HS Nylon that's interesting. Well I would have thought that HS Nylon would be hydroscopic enough to provide a built in HT coating all by itself. Is it too dry where you are to just depend upon ambient moisture for this? It sounds like you still need a coating geez you have to put Nylon on your Nylon to make it work that's a redundant system if there ever was one.
"You often don't see the problems associated with brainstorms until you try them" Aint that the humbling truth. I like that Jim ha, mistakes suck but in my old age I am coming to understand they provide the best learning opportunities there are.
I also tried the upside down with solvent idea but I misted the louver several times first to soften it up then wet it with solvent one last time and placed it on a set of wires which had been pre strung on a on another frame then I placed an oversize plate of glass and some steel weight on top of the glass. The idea was to push the louvre into the wires and the oversize plate glass was to keep the solvent down at the surface of the louvre and not to let it evaporate away. Previous attempts with a bath of solvent were a messy mistake. Neither method was good enough to entice me to put up with the fuss. Thanks for the kind offer we can talk off line later. The 24 wires per inch was easy all it took was a couple of lengths of 24 threads per inch 1/4 inch threaded rod and a bunch of finishing nails. I got some 32 per inch rod and would like to try that out. I think the best combination is a piece of insulated perf metal bonded to a louver. This will have no stray capacitance at all and the perf metal should add strength to a louvre as well. A nice combination. I did not mention due to a mental lapse that the water based Acrylic epoxy paint might be doctored to be resistive enough and it might come in at about the same weight as the Acoustat coating. It bonds to Mylar very well but it is heavier than I would ever want to use on a project of my own. Have to run but I am sure that we will talk later Jim. Regards.
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Old 12th April 2010, 08:58 AM   #44
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I have different width panels. The one pictured is 9" of diaphragm width. I also have some narrow panels. HS80 is good for wide panels. I was struggling to find my pictures of assembly and so far have not been successful. I took pictures of my hot wire cutter and curved jig during construction but I have not found them yet. I could post pictures of the hot wire cutter and curved jig, but it would not be as informative as the ones with the panel being wired.

I was toying with the idea of using a whole sheet of the louver with three sections. 2 on the outside of equal width and a center narrow. I guess that would be "Acousta-Quad"

Stability: Yes the heavier is used on bass panels. The felt damping is also used on the rear of the panel. If you don't use it, they will bottom out and they will sound boomy.
I have found that if I don't play them for a few weeks, they will sometimes collapse until you apply drive..then they snap back into operation. The felt pattern is similar to what Strickland used.

Dupont does not make the Nylon HS. As I recall it was American Biaxis. I don't know if they are still around. A Google search for nylon films may result in some suppliers.

I had thought that I could use the nylon without a coating. This was not the case. They sounded very "thin". Also, the dimensional stability issue was not a problem on the narrow panels.

Later,

Jim
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Old 12th April 2010, 04:52 PM   #45
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Default oops lets try this...

three section two way panel.
Attached Images
File Type: jpg ESL Panel 3 section 2 way.jpg (54.1 KB, 322 views)
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Old 13th April 2010, 01:35 PM   #46
tyu is online now tyu  United States
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Default Moray Great panel

Moray
Allen here have good news on ESL,s, an you mint allready NO! cvb@peoplepc.com
thanks
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Old 13th April 2010, 02:05 PM   #47
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Looking into the wire part now.
I see that magnet wire is available with a nylon coating.
Is this recommended.
Previously, when we were talking about bonding the wire to the louver panel and the glues used, was that for pvc coated wire (Acoustat), can these glues be used on nylon coated wire.
Paul
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Old 13th April 2010, 03:22 PM   #48
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capacity :"As a manufacturer of ESL I need to say that those panels were state of the art at that time. You shopuld consider that we talk about a construction which was designed in the middle of the 70's !!! Todaxy you would do some things better, but the principle is sophisticated."

I thought that Acoustat was a great design and I decided to improve upon it, as every review I have ever read about them was good.
I was even more shocked when I found out how cheaply they were constructed for the price they were selling for. jer
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Old 13th April 2010, 04:07 PM   #49
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Hi,

yes the acoustat are still "good", but time goes by and in our days the acoustat design wont be competitive anymore (imo).

Regarding pricing:

If you would be a manufacturer, you might wonder yourself how much additional cost adds to the product itself. Means just about 30 % of the selling price in the hifishop belongs to the manufacturer. And he has to pay everything from it, material, stuff, building, energy, packaging, shipment, development of new products, warranty savings................

BTW: What do you think how many labour hours are needed to make something like a spectra 66 (pair of it) ready to ship ???

a: 5 hours
b: 10 hours
c: 15 hours
d: 20 hours
e: more than 20 hours


Capaciti

Last edited by Capaciti; 13th April 2010 at 04:11 PM.
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Old 13th April 2010, 04:54 PM   #50
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Compleatly understood, as my original plan was to bring it to the masses cheaply for those whom do not wish to undertake the construction process.
Unfortunatly the electronics require a cost about 50 to 100 times the cost of the materials of the panels them selfs.
Except of course when mass produced by the 1000's.
I am not familiar with the spectra 66, but with any type of model the answer would be ,e.
But I can forsee a small system like what I am working on at the present done with injection molding and smaller transformers with built in low to medium power chip amps for the desktop.
What I have right now is over kill for that application pushing only about 35 watts maximum.
IMO that would be at least a ten fold increase in performance over what is available commercialy especialy in the $200 to $300 range.
If one was to spend that kind of money on a desktop system ,anyway,why not have the best sonicaly as well. jer
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