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Old 6th October 2013, 02:33 AM   #11
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Well, I have spent the last day or so pouring over info from the cookbook and this forum's archives, and I'm still making my mind up on my proposed design/plans....time will tell, I guess.

@ jer,
Wow, sounds like a killer little panel! When are you going to make the new one? ...cant' wait!

If you could find that paper you mentioned and post it that would be great. The clip you posted of Roger I have seen many times and agree with all. *Except* When he says that a curved ESL sounds like a regular dynamic speaker..haha.. I couldn't disagree more.
Anyway, I mentioned that I have a set of flat panels that are on their way out, and my plan for them is to disassemble those, have them sandblasted, and re-do them from the ground up.

Those panels have served me well and sound great in the sweet spot, but (and this is going to sound strange) I find myself listening only to recordings that sound exceptionally good, and avoiding others that don't.
Have you ever listened to Zeppelin III on ESLs? It sounds like the crappy recording that it is, about the only thing I notice is that you can now hear Bonham's squeaky bass-drum pedal on 'Since I been loving you' in all it's gory glory..lol..

I'm still going to keep the flat ESLs for critical listening, but I really want to build a curved set *deliberately* to avoid this 'magnifying glass' effect that I get with them.

All that being said, I still would like for someone knowledgeable about the electronics of ESLs to tell me rather Jazzman's setup would work with panels, say, 14" by 60" in size.

Out for now...
-wreck
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Old 6th October 2013, 02:41 AM   #12
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Quote:
Originally Posted by Calvin View Post
Hi,

If You still decide for curved punched metal sheet stators, than be prepared to put a helluf preparation time and work into the things if You want SotA results. And do Yourself the favour to get the right and the best materials.
3/8" or 3/16" is not a question, but the road to hell.
And be prepared to maybe be in need of a different amplifier, as most solid state amps are incapable of pressing the ultimate out of the speaker

jauu
Calvin
Hi Calvin,
Could you describe what you mean in the sentence I put in bold above?
BTW, I laughed out loud when I saw it with the little rain-cloud emoticon haha..
You also mentioned insulating making my hair gray, could you expand on that too? I would appreciate it.

cheers
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Old 6th October 2013, 11:38 AM   #13
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So far I have the new panel already made but I have yet to put the diaphragm on it.
I have its build completely documented in detail here,

A Segmented Stator Desktop ESL

Here is a short thread on the old panel before it finally gave out,

A Desktop ESL Build

Had I not pushed it so hard, they would still be working, But it was all done in the name of DIYAudio science!!

As I had mentioned before but in other threads, I used Powder coating on the original window screen stator, and then was later resealed with some clear acrylic spray paint when I refurbished them and got them running again in 2010.

I am planning on building an identical panel using the same construction methods I used before, only using the new improve painting method that I have done here,

High strength Dielectric Coatings, fact or fiction

I also have some bulk PC material and try that method again sometime once I get a liquidizing bed made to dip the stator screen's into for coating them.

I haven't totally abandoned the curve panel idea yet as I think that it might work very well for my smaller panels.
But for a larger width panel, I think that the electrical segmentation method just may be the ticket.

I get approximately up to 15 degrees off center of high end dispersion with my 3.25' wide diaphragm as measured.
It seems to coincide with the math formula's and simulation programs I have used.

Past that you start to really notice the difference as the highest frequency's start to drop off considerably.
Using electrical segmentation I am hoping to increase it to 30 to 45 degrees off center if not better.

I will look for that link for you, I think I have it posted in one of these threads.
It is a great book!

It explains in great detail about panel width vs dispersion and the problems involved with curved panels.
Such as the phase issues on the wavefront due to the center of the panel being closer to you than the the waves coming off of the edges as they are slightly farther away.

Yes, I do have the same issues with some listening material as you!!

ESL's recreate the sound with such precision that only best recordings and mixes sound good and if there are any flaws the are greatly enhanced!!!!

Yes, I do recall that squeaky Kick pedal!!
That happened to me to me once doing a recording session for a band and it took us hours to figure out what that horrendous noise was!
Needless to say the on the next session the drummer had got a brand new pedal and it was all good after that.

I had a very hard time listing to some of the Zepplin stuff and especially Pink Floyd's "Dark Side of the Moon"!!!
You can here every little click and tape splice, or when a track pops in and it is not exactly the right level yet.

Then there are other recordings that are very well edited and just sound Phenomenal like ELP's "From the Beginning" and "Lucky Man".

Spandau Ballet's "True" is another great vocal track but the kick drum click reaps havoc for my smaller amplifier!!

Much of David Bowie's stuff is good and the Spin Doctors just rock on my little panel just to name a few.

Jazzman helped a fellow friend and DIYer "Mavric" build his panels and they were about 16"wide and there is a few threads on that build Here,

Start to Finish ESL Hybrid

And here,

Material for ESL

jer
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Old 6th October 2013, 12:30 PM   #14
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One of the papers I have is from Frank Verwaal, and it can be found here,

experiences with ESL directivity?

The other one is called,

"Wide-Range Electrostatic Loudspeaker with a
Zero-Free Polar Response" by D. R. White.

It is an AES Paper, I don't remember how I obtained it as it was either sent to me or I stumbled on it during a google search one day as sometimes I do find every once in a while whole books in PDF format that you otherwise have to pay a fee for, therefore I don't have a link to it, Sorry.

jer
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Old 6th October 2013, 01:14 PM   #15
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Just for your enjoyment I stumbled on the pictures of that little panel that burned up !!!

ESL woofer- anybody game?

I was trying to see if the link to that paper is in here somewhere, But no such luck yet.

jer
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Old 6th October 2013, 02:08 PM   #16
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Thanks jer, guess I'll be reading a lot of the links you posted today.

I keep forgetting to mention the amp I use, and will be using unless something unforeseen happens.
It's an Emotiva XPA-5, and it's a fairly heavy hitter, here's are some partial specs copied from their website:

Quote:
Specifications XPA-5

Number of channels: 5
Topology: fully discrete, highly optimized dual differential, high current, short signal path Class A/B with premium components throughout
Power output (all channels driven):
300 watts RMS @ 4 ohm (0.1% THD)
200 watts RMS @ 8 ohm (0.05% THD)
Rated power bandwidth: 20 Hz to 20 kHz +/- .075 dB
Broadband Frequency response: 5 Hz to 100 kHz, +0 -2dB
Amplifier gain: 29 dB
Signal to Noise Ratio:
1 watt: > 95 dB
Full power: > 119 dB
Input impedance:
unbalanced: 23.5 kohms
balanced: 33 kohms
Power supply: 1,200VA toroidal transformer with 60,000uF storage capacitance
Size:
unboxed: 17” wide x 7 3/4” high x 19” deep
boxed: 23 1/2" wide x 12" high x 24 3/4" deep
Weight: 70.4 lbs (81.5 lbs boxed)

XPA-5 | 200W x 5
So far I'm happy with it, we'll see though...

I also keep forgetting to mention that the electronics to my current flat ESLs was something that came with the panels.

About the only details I know of is that the bias supply feeds both panels, and that the step-up transfos are 50:1.

While they seem to work fine, I'm sure there are advantages to be had if I were to do build brand new, for instance, it would be great if the bias were variable, and each panel had it's own supply, I also would like the tranfos to have a larger step-up ratio.

As it is though with that amp, these can play ear-splittingly loud without the amp even breaking a sweat, but the dip to around 1.2 ohm at the higher frequencies makes me think that a higher step-up ratio would be safer in the long run. (better safe than sorry, and all that)

There's also a shelving EQ that starts a boost at 1kHz and rises down to the 400Hz area (not 500, [typo in earlier post) where they are crossed over.

All electrical components (EQ, transfos, bias supply) are stuffed into the same box that sits in the equipment rack, and the ESL wires run attached to the basement beams, then down inside the wall where they terminate to a plate type connection.

PS, thanks for chiming in bear, had a look at your amps on your page, awesome stuff bro..
Very true that anything I build is going to be a compromise/trade-off, just trying to decide which ones I wanna live with is all..

Have a great Sunday y'all...
cheers
-wreck

Last edited by wreckingball; 6th October 2013 at 02:25 PM.
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Old 6th October 2013, 03:06 PM   #17
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It was the Frank Verwaal paper that had the info that I was referring to.

Keep in mind that if you increase your transformation ratio then it drops your overall impedance as well.

Therefore doubling the ratio increases your efficiency by 6db but drops the impedance by half as well.
Even though the amp may not have to work as hard to reach a certain SPL so there are some trade offs to consider.

Everytime you double the bias voltage this also increases the efficiency by 6db as well providing that your stator coating is up to it and doesn't arc through

It is safer for the amp to raise the Bias voltage than to raise the transformation ratio.

If your amp is capable of a high voltage swing then the lower ratio would be better if it is not suited for 2 ohm use.

The other thing to keep in mind is that due to the raising response of the panel and if EQ'ed properly, the low impedance at the highest frequency's is not so bad on the amplifier in the long run because it will be some 10db to 20db down compared to the midrange.

A slope of 6db per octave is equal to 10db per decade.
Considering a range of 200hz to 20Khz, There is a raise in the response of 20db that has to be compensated for in order for the panel to have a flat response at a distance, due to the dipole action of the driver.

Also you must consider the transformers stray capacitance as well as the panels capacitance when you determine your overall final impedance from your transformation ratio.

This is usually not so bad for larger panels.
But it is a big issue for my little panel designs as the transformers capacitance is much larger than my small panel by as much as 4 to 10 times.

Plus for comparison, The little panels don't have the surface area advantage of a large panel and that was why I had to push the voltages to such extreme levels to make them perform as well as they do.
Although, Once I start building a larger system, I will be applying what I have learned about the really high voltages to them as well!!!

FWIW

jer

Last edited by geraldfryjr; 6th October 2013 at 03:25 PM.
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Old 6th October 2013, 04:15 PM   #18
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Quote:
Originally Posted by geraldfryjr View Post

Keep in mind that if you increase your transformation ratio then it drops your overall impedance as well.

Therefore doubling the ratio increases your efficiency by 6db but drops the impedance by half as well.
Even though the amp may not have to work as hard to reach a certain SPL so there are some trade offs to consider.

Everytime you double the bias voltage this also increases the efficiency by 6db as well providing that your stator coating is up to it and doesn't arc through

jer
You just saved me a possibly huge headache, thank you!

See? That's why I'm so glad I started this thread, I would probably have missed or glossed over this basic but very important info in another thread, but because it's here, I got it.

I looked for a repository of basic rules for wrapping all of this ESL building stuff up online but didn't find one, sure there's tons of info out there, but it's so widely scattered, and with so many variables, that it's difficult for a beginner.
I just borrowed back a copy of Sanders cookbook so that should help.

So it's on to researching panel insulations and bias limits for a given panel...(I think).

I already ordered a can of Licron crystal spray per Jazzman's blog, please tell me I didn't waste fifty bucks...please?

Last edited by wreckingball; 6th October 2013 at 04:22 PM.
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Old 6th October 2013, 04:26 PM   #19
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Nope, Licron Crystal is awesome stuff, expensive but works great!!!

I have been meaning to make a sticky post with all of the more favorite informative threads but I just haven't got around to it yet.

I have a couple of posts that list many of the links already, But yes they get buried easily.

jer
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Old 7th October 2013, 12:23 AM   #20
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Just to throw some tomatoes into the mix...

...one word: Beveridge.
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