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Old 2nd June 2010, 02:31 AM   #1
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Default Help, Advice, Information, Reassurance... ???

I have done minimal research into ESL, its been 3 days now. I can find a multitude of DIY information, but not many large scale first time successes. The feeling from my impressions is that this would turn out to be pretty difficult. I guess I just want to know if it is as complex as it looks to be. Mind you, I have limited resources as a father of 2 and the sole provider. I would love to attempt something like this but am unsure if this will end up being a never ending money sink that I just cant collect on. Although it sounds as though the payout is awesome!

My wife is so tired of my going on and on about how much I hate cheap/expensive speakers sounding like the grand canyon. What actually brought me here was the fact that I planned on attempting to build my own balanced system from the floor up. If I can do that with directional sound, all that much more amazing to me.

Any tips/advice would be SO appreciated.
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Old 2nd June 2010, 11:24 PM   #3
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Thanks for the links, I've already read a great many of them, but it is a good starting point.

Onto another problem that occurred to me. Is there any way to "child proof" these types of speakers without losing a whole lot of quality or volume? I've read about everywhere that the shock from these as they're active is pretty terrible. To quote something I read somewhere, "it hurts terribly and smells just as bad". Not exactly something I would like my one year old to have to go through if you can respect that... heh.
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Old 3rd June 2010, 12:40 AM   #4
Few is offline Few  United States
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Building a world class, every-detail-optimized ESL isn't a trivial undertaking.

On the other hand, building an ESL that has many of the properties that makes these systems so attractive isn't so tough. I'd recommend using perforated steel stators, and double-sided 3M foam tape for spacers (see McMaster-Carr online for supplies). You can even find relatively inexpensive ways to assemble suitable step-up transformers and bias supplies. Finding a decent coating for the stators isn't trivial, but I've had acceptable success using epoxy spray paint (like you'd use to repaint kitchen appliances). Others can suggest alternatives.

I'd recommend building a small and cheap prototype panel to be sure you're on the right track. If you can get it to make sound, then you'll have learned enough to go for broke.

The safety issue may be trickier. If there'll be toddlers around, I'd not recommend relying on the stator coating to prevent shocks. You can really get a jolt if the music is playing and someone finds a gap in the coating. Perhaps you could come up with another acoustically (nearly) transparent method to prevent probing fingers from getting into trouble. An outer perforated metal screen that is grounded might do it. It would obscure the sound a bit, but it's better than risking a nasty accident. Designing the system so the stators don't extend down to the floor would help a little, but that won't help much if the youngsters are already walking around.

Bottom line: It's not hard or expensive to be build ESL panels that you'll really like. I'd plan on using the panels only down to 200 or 300 Hz, though, so you'll need woofers to fill in the bottom end.

Few
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Old 4th June 2010, 12:52 AM   #5
a.wayne is offline a.wayne  United States
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An ESL as your first project could be pretty daunting, what is your budget? there are good qualty panels from acoustat ( esl ) or maggies ( planer magnetic) that can be obtained in the 500-700 dollar range.

I would start with one of these first , get used to what they do, you can Mod them with upgrades, add subwoofers etc.... This might be much better for you than starting something you might never get done or like ...


well unless you have to DIY ....


Here are 2 examples:

AudiogoN ForSale: Acoustat Model 1

Magnepan Mg 12 Qr Cherry+Black Fabric For Sale | AudiogoN
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Old 4th June 2010, 01:49 AM   #6
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Quote:
Originally Posted by USMCBrown View Post
Thanks for the links, I've already read a great many of them, but it is a good starting point.

Onto another problem that occurred to me. Is there any way to "child proof" these types of speakers without losing a whole lot of quality or volume? I've read about everywhere that the shock from these as they're active is pretty terrible. To quote something I read somewhere, "it hurts terribly and smells just as bad". Not exactly something I would like my one year old to have to go through if you can respect that... heh.
The removable grills on my ESL's would provide a level of shock protection for toddlers and they don't significantly affect the sound quality or volume. The grill cloth is rather thin but you could back it up with a grounded open mesh wire screen as Few suggested and I'm sure that would provide 100% protection. My stators are coated with 12-14 mils of polyurethane and I've touched them directly while playing and I've never gotten shocked anyway.
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Old 4th June 2010, 02:05 AM   #7
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As Few said, you shouldn't rely on the stator coating alone for protection against shock and I hope I didn't imply that in my previous post. As you can see in the photo below, I used a wire screen over the woofer opening on my grills to protect the woofer from being accidentally kicked. The open wire mesh I used would not affect the sound of the electrostat at all in my opinion.
Attached Images
File Type: jpg 005.jpg (430.5 KB, 341 views)
File Type: jpg 012.jpg (496.2 KB, 334 views)
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Old 6th June 2010, 11:25 PM   #8
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As I'm looking for materials I thought of a few more things that may or may not make a difference.

1- I've seen minimum 40% to 60%+ minimum for open area of stators. Is there any significant benefit to have more/less?

2- Is there a sweet spot distance for putting a beam splitter? And does it matter what material the splitter is made of?

3- Metal type of stator? aluminum/steel, pro's/cons?

4- I figured I would make mine like 12"x40-48". Where should I expect to have to put the crossover? I've seen some conflicting results. I realize this has to do with many variables, but as a round about starting point.

5- Are all power supplies made equally? There seems to be a multitude of cheap to expensive power supplies. Any real differences other than adjustability range? Or is there no effect to the sound quality regardless of what I chose to use?

6- Stator hole size? Various ranges again, does this effect speaker range or anything of the like? Or is it just a sound quality risk going bigger/smaller.

I've found multiple answers for most of these questions, but have yet to find any real definitive explanations or answers. The help is much appreciated, and I'm sure I'll have more questions.
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Old 7th June 2010, 02:00 AM   #9
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Quote:
Originally Posted by USMCBrown View Post
As I'm looking for materials I thought of a few more things that may or may not make a difference.

1- I've seen minimum 40% to 60%+ minimum for open area of stators. Is there any significant benefit to have more/less?

2- Is there a sweet spot distance for putting a beam splitter? And does it matter what material the splitter is made of?

3- Metal type of stator? aluminum/steel, pro's/cons?

4- I figured I would make mine like 12"x40-48". Where should I expect to have to put the crossover? I've seen some conflicting results. I realize this has to do with many variables, but as a round about starting point.

5- Are all power supplies made equally? There seems to be a multitude of cheap to expensive power supplies. Any real differences other than adjustability range? Or is there no effect to the sound quality regardless of what I chose to use?

6- Stator hole size? Various ranges again, does this effect speaker range or anything of the like? Or is it just a sound quality risk going bigger/smaller.

I've found multiple answers for most of these questions...
There are many opinions and mine isn't better than others' but I will share my thoughts on your questions:

1) The stators' open area is a compromise. Less open area means more metal carrying charge to drive the diaphragm; whereas, more open area means less obstruction for the sound emitted from the diaphragm. Panasonic did a study which showed that maximum air velocity thru the stator occurs with 42% open area. I've tried 40% open and 51% open stators both sound great-- I really can't hear a lot of difference between them.

2) I don't know if there is a sweet spot or best distance for a beam splitter or even if it's a good idea to use one at all. In my case, I made my bass box a beam splitter not for dispersion but because it allowed me to merge a large volume transmission line bass box in the same space with a tall, line-source electrostat. It also allows placing the speaker in a corner or directly against the wall but who's to say a fully open dipole without a beam splitter wouldn't sound better in some respects? All designs are a compromise.

3) I like steel over aluminum because you can solder the wire lead to it and I would think that it's higher mass would make it less prone to ringing-- an important consideration when using thinner material.

4) On my 12x48 panels, I have the crossover at 275 hz and I do have to apply EQ to compensate the dipole cancellation. I think that size and crossover are a pretty good compromise but, again, it's a subjective thing.

5) Power supplies and electronics in general are definitely not my forte so I will defer to others on that. Sanders' Cookbook recommends around 50 volts per mil of diaphragm/stator spacing and the power supplies shown in his book are simple half-wave ladders with no special provisions to smooth out the ripple so I guess ripple isn't a major concern for Sanders. Since I have no talent for electronics but I can solder pretty well, I shamelessly copied the basic circuit for my power supply from a speaker I saw online that had similar stator area and 1/16 d/s spacing-- it works fine and only costs $20 to build.

6) Hole size is also a compromise. Ideally, the hole size wouldn't be larger than the d/s spacing and smaller holes would yield a denser, more uniform charge driving the diaphragm with greater efficiency. In the real world, there is a practical limit to how small the holes can be because the diameter needs to be at least twice the stator thickness; otherwise the holes become cylinders and the air mass in the cylinders have an impedance which attenuates the treble-- so, as the holes get smaller, the stators must get thinner and more prone to audible ringing. Also, there are only certain perf sizes and thicknesses readily available at a reasonable price. I've listed three sources on my blog page. The bottom line for me is that I would not go with holes larger than 3/16" diameter.

Jazzman
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Old 7th June 2010, 02:11 AM   #10
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Quote:
Originally Posted by USMCBrown View Post
As I'm looking for materials I thought of a few more things that may or may not make a difference.

1- I've seen minimum 40% to 60%+ minimum for open area of stators. Is there any significant benefit to have more/less?

2- Is there a sweet spot distance for putting a beam splitter? And does it matter what material the splitter is made of?

3- Metal type of stator? aluminum/steel, pro's/cons?

4- I figured I would make mine like 12"x40-48". Where should I expect to have to put the crossover? I've seen some conflicting results. I realize this has to do with many variables, but as a round about starting point.

5- Are all power supplies made equally? There seems to be a multitude of cheap to expensive power supplies. Any real differences other than adjustability range? Or is there no effect to the sound quality regardless of what I chose to use?

6- Stator hole size? Various ranges again, does this effect speaker range or anything of the like? Or is it just a sound quality risk going bigger/smaller.

I've found multiple answers for most of these questions...
There are many opinions and mine isn't better than others' but I will share my thoughts on your questions:

1) The stators' open area is a compromise. Less open area means more metal carrying charge to drive the diaphragm; whereas, more open area means less obstruction for the sound emitted from the diaphragm. Panasonic did a study which showed that maximum air velocity thru the stator occurs with 42% open area. I've tried 40% open and 51% open stators both sound great-- I really can't hear a lot of difference between them.

2) I don't know if there is a sweet spot or best distance for a beam splitter or even if it's a good idea to use one at all. In my case, I made my bass box a beam splitter not for dispersion but because it allowed me to merge a large volume transmission line bass box in the same space with a tall, line-source electrostat. It also allows placing the speaker in a corner or directly against the wall but who's to say a fully open dipole without a beam splitter wouldn't sound better in some respects? All designs are a compromise.

3) I like steel over aluminum because you can solder the wire lead to it and I would think that it's higher mass would make it less prone to ringing-- an important consideration when using thinner material.

4) On my 12x48 panels, I have the crossover at 275 hz and I do have to apply EQ to compensate the dipole cancellation. I think that size and crossover are a pretty good compromise but, again, it's a subjective thing.

5) Power supplies and electronics in general are definitely not my forte so I will defer to others on that. Sanders' Cookbook recommends around 50 volts per mil of diaphragm/stator spacing and the power supplies shown in his book are simple half-wave ladders with no special provisions to smooth out the ripple so I guess ripple isn't a major concern for Sanders. Since I have no talent for electronics but I can solder pretty well, I shamelessly copied the basic circuit for my power supply from a speaker I saw online that had similar stator area and 1/16 d/s spacing-- it works fine and only costs $20 to build.

6) Hole size is also a compromise. Ideally, the hole size wouldn't be larger than the d/s spacing and smaller holes would yield a denser, more uniform charge driving the diaphragm with greater efficiency. In the real world, there is a practical limit to how small the holes can be because the diameter needs to be at least twice the stator thickness; otherwise the holes become cylinders and the air mass in the cylinders have an impedance which attenuates the treble-- so, as the holes get smaller, the stators must get thinner and more prone to audible ringing. Also, there are only certain perf sizes and thicknesses readily available at a reasonable price. I've listed three sources on my blog page. The bottom line for me is that I would not go with holes larger than 3/16" diameter.

Jazzman
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