[captainjack115]

I've been designing and building ESL's since I was 14, I'm now 72.
A brief mention of my humble credentials includes:  Recording and Broadcast Engineer, Inventor, and Author.
I first heard about Roger from reading articles in Speaker Builder magazine concerning ESL construction projects.
I have a few observations/ queries  I've been thinking about for some time.
Back in the early 80's Roger and I communicated through snail mail and phone calls, discussing various aspects of ESL design. He sent me an advanced copy of his compact ESL/TL manuscript due for a later publication in Speaker Builder. A nice gesture!
In retrospect and reflection, there are some things I find odd. I had designed and built a variable output high voltage bias supply to carry out my own R&D on ESL's.
Roger asked if I would be willing to send it to him so he could play around with it. I declined.
Much of human knowledge has been learned through empirical effort. With that in mind, if we look back at some early Speaker Builder issues, Roger was making his stators from Lincaine sheet metal and had no use whatsoever for any sort of insulation. His assertion being that the air gap between cell elements was all that was necessary.
With that mindset in place I suggested a stator design that provided high field density, albeit uninsulated. He was kind enough to mention me by name in his next Speaker Builder project. Thank you Roger!
When Roger published his "Electrostatic Loudspeaker Design Cookbook", he wrote of my stator design once again, this time uncredited. Oh, well!
Overall, kind of a nice book for the average DIY hobbyist that want to hear music come from something they made with their own two hands. Personally, Ronald Wagner's book has a lot more ESL theory for the serious ESL builder.
Years later Roger fell into some incredible luck by meeting up with Raj Varma and involved himself with Innersound.
I contacted Roger by email saying I had considered starting my own line of ESL's. I was met by extreme negativity. I'm paraphrasing here: That's a terrible idea, you'll lose your shirt!
Here's the real kicker! He claims he doesn't remember who I am!
Hello? The snail mail? The phone conversations? The manuscript?
By the way!  How does a clinician from Half-Way Oregon become a self proclaimed scientist? Must be humble beginnings, a lot of us start that way I guess. Also an ESL is only a capacitor when measured from the actual cells.
Looking over the Sanders Sound Systems site, I have concerns. Wow! $17,000 for a complete speaker system? How many average people could afford that kind of money for a personal indulgence?
This is a "very" niche market. Another concern is the "Lifetime Guarantee". Who's lifetime? This is a boutique business run by a man in his 60's. If something happens to him, where does one go for repairs or technical problems.
Please, I don't want anyone to mis-interpret. I'm not trying to flame Roger Sanders, this is my personal experience and I have concerns.

[Jazzman53]

Hi Captain Jack,

I had no idea there were other members on this forum who build ESL's, let alone anyone with your years of experience.  It's a pleasure, sir.

Around 2008 I had a few phone conversations with Roger myself and I found him to be very helpful and pleasant.  I thanked him for writing the Cookbook and I implied that I couldn't afford to buy his speakers and was only interested in building a pair for my own personal use (not to sell).  Possibly my conversations with Roger took a different tack than yours because he didn't perceive me as a potential competitor; especially as it was quite obvious that I had no electronics experience. 

Anyway, thanks to Roger Sanders and a couple of other ESL gurus on the DIY Audio Forum, my fist ESL's built in 2008 turned out quite well.  They were even featured in the April 2012 edition of AudioXpress magazine.

Since that time my speakers have evolved through several generations of stators and crossovers but I've retained the original beam splitter transmission line bass section; although mine are quite different from ones you mentioned that Roger built. 

My latest speakers (built last year) will appear in the September 2017 edition of AudioXpress-- wherein the article gives substantial credits to ESL gurus Rod White and Steve Bolser (a.k.a. Golfnut and Bolserst on the DIY Audio Forum).  I've learned much from others and I feel a profound obligation to credit my success to those who helped me along the way.

I agree with you about Ronald Wagner's book.  His panel design, which he described how to build in extra-ordinary detail in his book, didn't really appeal to me but I found his explanations of ESL theory enlightening.

Roger's book was quite good with respect to guidelines and he certainly blazed a path for others to follow but it's rather outdated now.

It's really too bad that the smartest ESL builders on the planet seem to have no interest in writing a book on the subject.  I would do it myself if I had the smarts.  I do pretty well with the mechanical aspects but the electronics are a struggle for me.

I suspect Roger Sanders isn't getting rich building speakers and he won't compromise to make them economical so perhaps that is why he attempted to discourage you from getting into the business... after all; building ESLs is rather a psychosis, don't you think?

Charlie

   


 

[captainjack115]

Hey Charlie

First off, I want you to know I've visited your site several times in the past
before this writing.
I can't begin to tell you how impressed I am with your work and just how well
you have executed the entire site. Your woodworking skills are especially
outstanding, great job on the ripples! I had a local cabinet maker build
a set of "H" frames for me because I have virtually no woodworking skill.
I actually showed him a photo of your ripoles and he wanted a lot more
money than I was willing to pay.
I did something unusual with the "H" frames though.
I have a Mini DSP and programmed it for dipole configuration,
but I also have a configuration for a sealed system by flipping the "H"
frames face down on a self sealing surface.

Getting back to my comments concerning Roger Sanders,
I suppose it could sound like I was nitpicking a bit.
Our conversations were always friendly and cordial on both sides, and
he has shown himself to be intelligent and articulate.
In fact, we have much aligned thoughts on many things concerning
the reproduction of music.
In my younger days I not only recorded live music, but cut master
discs as well.
I can tell you without hesitation that analog discs are far inferior to
today's digital recording systems. Roger and I are in full agreement.
It would seem ludicrous to say that Edison's wax cylinder was better
than a disc, but at least it would have constant velocity.
About an hour ago I spoke with my friend Moray James, of "Moray
James Cables" about my recent post regarding Roger. he thinks it
came off a little strong. I was just trying to share my concern/experience.
By the way, Moray James makes extremely good cable products, using
high quality materials.

I'd enjoy discussing ESL design techniques with you and anyone else.

Jack

[Wind Chaser]

In my younger days I not only recorded live music, but cut master discs as well.
I can tell you without hesitation that analog discs are far inferior to today's
digital recording systems. Roger and I are in full agreement.

I'm in full agreement with you and Roger as well.

[Jazzman53]

Hey Charlie

I'd enjoy discussing ESL design techniques with you and anyone else.

Jack

Hello again Jack,

I’m amazed that you were building ESL’s way before the internet enabled guys like me to learn how it’s done.  I can only imagine the pitfalls you might have gone through building your first speakers; especially with regard to the diaphragm coatings and transformers.

It brings to mind my very first ESL panels, which played wonderfully for all of a couple of minutes until I cranked up the volume and the corona streaming off sharp points along the perf metal stators’ edges quickly burned through the paint coatings and started arcing between stators.  There was so much arcing it sounded like an old manual typewriter going and the air smelled of ozone and smoke from the foam tape spacers igniting.   

Fortunately, both of my vintage Carver amps sensed the shorting and went into protection mode but the panels were a total loss.  I ended up having to completely re-do them; only saving the metal.  The stators were coated with a two-part catalyzed polyurethane which was a nightmare to get off; requiring several days and multiple applications of a chemical paint stripper and lot of wire brushing to remove all the paint form the hole perforations. 

That was a hard lesson to learn and on subsequent builds I became obsessive about smoothing away every single sharp point on all cut edges of perf metal stators.  This is only a theory-- but I also concluded that the high-dielectric tape I used to over-wrap the stator edges may have done more harm than good by focusing the corona back to the emission points on the stator rather than allowing it to dissipate into the surrounding air—this resulting in rapid burn through of the paint coating and snowballing intensity of the corona.  Based on that theory, I started wrapping the stator edges first with foam tape (lesser dielectric) and then over-wrapping the foam tape with the higher dielectric polyester tape to contain the corona without burning thru the paint coating.   I never had a failure after that. 

Nowadays I’ve gone to insulated wire stators which have proven to be very robust and I have no concerns about arcing with my new speakers.

Charlie               

Below: A metal pinwheel charged to 10kV and resulting corona

[Mike B.]

I seem to remember Roger's writings going way back to the Audio Amateur. Give him credit for sticking to it and making a living at it. I have seen a review or two that praised his work.

[Jazzman53]

I've never met Roger Sanders or even heard his speakers but I would never have built an ESL had it not been for his Cookbook giving me the confidence know how to do it.  We had a couple of phone conversations and I've never talked to a nicer guy more willing to help.
 

[captainjack115]

Hi Mike
Yes I'll give Roger the respect he deserves for sticking to his guns and makin a living  building his own business  in Audio, not an easy task these days.

To Charley:
Nice pinwheel photo, worthy of wall hanging.
Which reminds me of something.
It's not often talked about, but a phenomenon occurs within an ESL cell that alters maximum output regardless of how good stator insulation may be. Once the electric stress within the air gap reaches 100 volts per mil, air molecules will ionize and nullify the polarizing voltage between the stators.
This phenomenon is generally not noticed on its own, but if you were to compare an ESL to a magnetically driven system the peak output would be lower from a the ESL.
Dayton Wright ESL's didn't have this problem because they encased their cell in a bag containing hexafluoride gas. The gas would eventually leak through the pores of the bag and required an occasional refill. Not worth the trouble in my opinion.
I started building my cells using #30 Kynar wire, about 12 wires per inch back in the mid 1980's They have good sensitivity, despite the ionization phenomenon, which otherwise is unnoticeable in practicality.
BTW, my first ESL's were single ended. At 14 I wasn't smart enough to realize the advantages of push pull design.
Yeah, that was a real pain for you having to clean up your steel stators after an arc-over. It's amazing how much current can build up during dielectric breakdown. You're lucky the amplifier went into shutdown protection.

Jack

[jwmorris]

I do not know much about Roger Sanders. I do not know much about electrostatic speakers either. I was fortunate enough to buy a used pair of Inner-sound Eros which Roger Sanders was heavily involved in bringing to market. I called Sanders Sound Systems prior to the purchase and Roger answered the phone. I called again, after purchase, with a question and Roger answered the phone.   

If you get a chance to audition these speakers do not hesitate. I have had to rethink analog, digital, and sound quality. My speakers are up-stairs and  I often listen at levels that won't disturb the rest of the house. The Inner-sound speakers are complete at any volume. The highs are there, the mid-range is there, the lows are there. There is no need for a additional sub-woofer, the panels sit on top of subs already. I now understand why some insist on active crossovers and using multiple amplifiers. Thank you to everyone that has or continues to push technologies and the enjoyment of music forward!

 

   

[captainjack115]

Roger is really great about answering his phone personally, as well as answering email. He's a very cordial man and will answer all questions to the best of his ability.
He certainty has come a long way since his 1980's diy ESL's made from Lincaine perforated aluminium.
Some ESL designs are more robust than others, Roger's Ultrastat speakers would seem to be superior to some other designs.
I've never heard his speakers but I hear good reports about them from people that have had a chance to audition them. He's a proponent of transmission line woofers , I have designed TL's over the years and they do have their merits. They exhibit smooth extended bass beyond Fs and are well controlled when designed and implemented properly.
Details aside, ESL's generally sound good, a combination of very low distortion and and excellent transient response are key points.
Adhering to basic design parameters, it would be really hard to come up with a bad sounding ESL. Even with poor or no insulation and questionable transformer quality. Even at a very basic level, the quality of sound produced is readily perceptible.
As for bass, that's a different story. Bass requires efficient movement of air with minimal diaphragm  cancellation. I had the good fortune to be able to divide a large room with a sand filled wall and installed multiple woofers as an infinite baffle. Very smooth, extended and powerful bass to accompany my ESL's.

[DrChaos]

I have heard the latest Sanders at the Irvine T.H.E audio show, 2 years in a row. Bi-amped, with digital crossover.  10D or 10E model.

Very narrow sweet spot. But within that sweet spot, the best recorded sound I've ever heard in my life. Best of show to me 2 years in a row, stunning and perfect.

I'm a fan of diversified classical and have a pretty good absolute acoustic reference.   If it weren't for the narrow sweet spot, I'd own it.

[Jazzman53]

I have heard the latest Sanders at the Irvine T.H.E audio show, 2 years in a row. Bi-amped, with digital crossover.  10D or 10E model.

Very narrow sweet spot. But within that sweet spot, the best recorded sound I've ever heard in my life. Best of show to me 2 years in a row, stunning and perfect.

I'm a fan of diversified classical and have a pretty good absolute acoustic reference.  If it weren't for the narrow sweet spot, I'd own it.

Being familiar with flat panel ESL's, I completely agree with your observations.  It's too bad that no speaker can provide both a wide sweet spot and the precise imaging you only get from an ultra-directional speaker like Sanders' model 10.  Actually, you can have it both ways-- just not at the same time:   

I once built an electrically segmented flat panel ESL using welding rods which had switch-selectable wide and narrow dispersion modes.  This speaker projected a precise image in narrow mode or a room filling sweet spot in wide mode. 

The switch mode feature was accomplished using a multi-pole rotary switch which engaged or disengaged (jumped over) the segmentation resistors.  Switching to narrow mode was rather a pain though because the panel had a flat frequency response in wide mode only (segmentation engaged), and required EQ'ing to compensate the dipole roll off when switched to narrow mode. 
     
Electrical segmentation is easy to do with a wire stator ESL by inserting resistors between the wire groups.  The segmentation also equalizes the panel's frequency response to essentially flat and presents a predominantly resistive load to the amplifier (as the amp then sees only the capacitance of the first segment). 
   
Adding the switch was a nifty feature but the novelty wore off pretty quickly due to my laziness of having to EQ the panel each time it was switched to narrow mode.  These days I use insulated copper wire-stators with segmentation, exclusively.  Here's a link to the build page and photos for my old segmented welding rod panels with the rotary switch box:  http://jazzman-esl-page.blogspot.com/2008/03/a-segmented-wire-stator-esl-with.html

It might be worth revisiting this idea to devise a speaker with only slightly wider dispersion than an unsegmented flat panel-- just enough to alleviate the 'head-in-a-vice" effect without giving up as much of its magical imaging.
   

[captainjack115]

These days I have a miniDSP in my system. A handy feature of this PEQ is the hand remote control unit with 4 presets.
One could easily provide equalization for multiple dispersion settings from the comfort the listening sweet spot.
I keep mine connected to my computer for tweaking purposes and/or changes in equipment

[captainjack115]

As an afterthought.

For a number of years I listened to a pair of ESL's that had narrow cells.
How narrow?
The cells were 4 inches wide, so they really didn't start to beam until around 3400 hertz. A point where the ear has it's greatest sensitivity and directional Que's.
So, 4 inches wide and 36 inches long, 144 square inches.. I used 2 of these cells part channel, stacked vertically, for a total of 288square inches.
Stator spacers were .125 inches, yielding around 1 pico farad per square inch, as I recall. Transformer ratio was 1/150, reflected capacitance as presented to the amplifier was about 7.2 MFD as calculated by the transformer's basic turns ratio only. Bias voltage was around 5000 volts.
Anyway, they were obviously line array's, and I mounted them in flat baffles, 22 inches wide, initially. I say initially because I added 11 inch wings using piano hinges
making the total width 44 inches during use. I'm not sure about the SAF/WAF, I cowardly kept them in the basement.
With my self designed EQ, I quite often listened to them (full range). Low to mid 80's SPL, not real efficient, but sounded nice, I liked the imaging.
When crossed over at 150 hz, 4 the order they played about 10 db louder.
The ramblings of an old man, I digress, a lo!
Back to my point.
I didn't have to lock my head in a vice to listen to them, the sweet spot was generous and forgiving.
Were they aesthetically pretty and/or beautiful? Well, no. But, they could have been if I had actually marketed them and charged a pirate's ransom for them.
Then they would have been "ESOTERIC"! I love that word.It makes the worst looking monstrosity's into works of art.

Where was I ? Did I mention the ramblings of an old man?

All kidding aside, pinpoint imaging can be great! With some recordings. Most recordings cranked out these days have been mixed in ways that can never be aurally reconstructed in any way that comes close to the real thing.
Recordings I hold in high esteem are binaural recordings made by David Chesky. Very nice, very real sounding.

In conclusion:
I don't get to do much with DIY these days, I mostly just sit at the computer and pontificate.
If it turns out that I'm occasionally wrong on a point or two. Be kind, and break it to me gently. 

[Pryso]

I can offer general agreement with DrChaos' comments.  However I think it is fair to add that the Sanders speakers were designed to project a narrow sweet spot.  Roger's contention is that is the best way to remove room reflections from the set up equation.  Narrower projection = less sidewall distance issue or reflection concerns.