Another ESL Project... the psychosis continues

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Jazzman53
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Another ESL Project... the psychosis continues

Post by Jazzman53 » Thu Mar 10, 2016 6:57 pm

Hi all,

The speaker building psychosis got the best of me again -- my new project is a segmented wire-stator type hybrid electrostatic speaker. Actually, not a whole speaker, just new panels to replace the welding rod panels in my old beam splitter ESL’s.

The photos show a stretching jig and stator wires being stretched to plastic deformation to make them perfectly straight and also work harden the metal so that they remain straight when the tension is relaxed.
The stator wires will be supported by wooden lattices (photo below). I think they're gonna look really nice.

There are 90 wires total, which will be segmented into (15) 6-wire groups. The center wire group will be directly coupled to the amplifier/step-up transformers and receive the full frequency band above 200 Hz. Moving from the center outward, the paired wire groups to the left and right of center receive discrete bandwidths that progressively step down in frequency. This is accomplished using an RC transmission line consisting of series resistors inserted between the wire groups which couple with the wires' capacitance to form first order filters.

The effect is that the flat panel electrostat now projects a cylindrical rather than planar wave front; giving wide dispersion and no beaming. The polar response will be far superior to a curved panel (like ML) and even better than most conventional speakers, while still retaining that magical ESL sound.

Got a long way to go here and a mile-long honey-do list impeding my progress—but I’ll get’er done sooner or later and I’ll keep posting build picks along the way.

Charlie

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BobSmi57
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Re: Another ESL Project... the psychosis continues

Post by BobSmi57 » Thu Mar 10, 2016 7:02 pm

I'm looking forward to following your speaker build, Charlie. I hope your idea for dispersion works well. That straight beam effect was a real drawback for esl speakers for me. They sure can sound magical in the sweet spot, though.

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kingman
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Re: Another ESL Project... the psychosis continues

Post by kingman » Thu Mar 10, 2016 7:11 pm

Looking forward to hearing this summer! Nice!!!
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Jazzman53
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Re: Another ESL Project... the psychosis continues

Post by Jazzman53 » Thu Mar 10, 2016 8:11 pm

BobSmi57 wrote:I'm looking forward to following your speaker build, Charlie. I hope your idea for dispersion works well. That straight beam effect was a real drawback for esl speakers for me. They sure can sound magical in the sweet spot, though.
Hi Bob,
I wish I could claim credit for segmented ESL's but I'm not that smart. Actually, it's now a tried and true concept developed by a couple of ESL gurus on the DIY Audio website. The even dreamed up an Excel spreadsheet that does all the math. I just plug in the height and width of the panel and diaphragm-to-stator spacing (for the capacitance calculations), number of segments, and the low frequency cutoff (where the panel crosses over to the woofer) and the spread sheet calculates the resistor values, max SPL, frequency response, and polar response. It's all over my head but I have smart friends :-)

My current welding rod panels are segmented also and they have great dispersion but they're butt-ugly and I wanted to try something that looks good also.

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radioeng2
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Re: Another ESL Project... the psychosis continues

Post by radioeng2 » Thu Mar 10, 2016 9:18 pm

Outstanding! Outstanding project Charlie. Man I'm glad to see you doing these and sharing it with us.

Your enthusiasm for the stat's is very infectious and really fired me up to hear you talk about it at CF.

I do hope to hear them. Keep us up on how it's going as they come together!

Mark
I was there "At the Fest!" Hope you were too!

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Magnaryder
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Re: Another ESL Project... the psychosis continues

Post by Magnaryder » Fri Mar 11, 2016 8:30 am

Now a small version of that would make a fun CarverFest build.

ray
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Don
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Re: Another ESL Project... the psychosis continues

Post by Don » Fri Mar 11, 2016 12:06 pm

Magnaryder wrote:Now a small version of that would make a fun CarverFest build.

ray
Boy, I second that!

Heard Charlie's stats last year when I dropped in on the way home from somewhere. Martin had my Carverfest speakers set up at Charlie's so I could demo and pick them up on the way home. Thanks again Martin for the fine assembly.

Let me tell you guys. Charlie's stats are the real deal. Heard several cuts on them and they sounded awesome. As good as any of the stats I have heard at any of the Audio shows Terri and I have attended. This man knows what he is doing. Also, his woodworking skills are top notch. A fine looking piece of furniture to boot.

If Charlie was retired, I would be on his doorstep, camp out for a number of weeks and twist his arm to help me build a set. They are that good.
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RIP BILL D. RIP WRABBIT

Jazzman53
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Re: Another ESL Project... the psychosis continues

Post by Jazzman53 » Fri Mar 11, 2016 2:40 pm

Mark,
I saw at Carverfest that you too are afflicted with the speaker building psychosis. There’s apparently no cure, as evidenced by the Bobfather still at it after all these years. BTW, I’m pretty impressed with your line array speakers too =D> .

And Don, thanks man. Coming from you, there can be no greater compliment.

I’m pretty excited about this new project. My one concern is that the stator mass may be inadequate. I’ve never built such light-weight panels before. Ideally, stator mass would be infinite, as it’s the anchor which the electrostatic force pushes against to drive the diaphragm. Even much heavier steel perf stators vibrate when playing so it’s a given that lighter wood slat/wire stators will vibrate even more. I’m just hoping the vibration won’t be audible. I’m thinking about looking for some adhesive-backed lead sheet (if such stuff is available) and stick some on the back stators for more mass.

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Re: Another ESL Project... the psychosis continues

Post by Jazzman53 » Fri Mar 11, 2016 3:06 pm

Correction: It’s more accurate to say that the stator’s mass is the anchor which the ES force pushes against to drive the AIR MASS. Yes, the diaphragm is driven, and it’s not lighter than air; however, it is much lighter than the volume of air it’s moving.
An ESL is remarkably non-resonant because it’s effectively swamped by the air mass it’s immersed in. It’s analogous to striking a bell immersed in liquid mercury—the bell in this case is so dampened by the surrounding mass that it simply cannot ring. If fact, the one and only resonance an ESL has is the diaphragm’s fundamental (drum head) resonance, which typically falls somewhere between 50-110 Hz.

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Re: Another ESL Project... the psychosis continues

Post by Jazzman53 » Mon Mar 14, 2016 5:50 pm

Update Monday afternoon, 3/14/16:

All woodwork completed-- temporarily dry-assembled the interlocking lattice pieces last night and today (no glue) and sprayed on the light colored stain and satin clear coat.

I've just started gluing up the first stator as I’m posting this. The first photo shows all four lattices after stain/paint. The second photo shows the first stator in the stretcher jig with the first 3 horizontal wire supports are glued in place over the wires. When the glue sets on those, I’ll move on to the next three.

I won't know for sure until I complete the first stator but it looks like this scheme is gonna work.

I stretched the 48" wires .50 inches, then relaxed almost all tension. I had to use larger diameter pins in my jig than what would have given correct wire spacing so I'm using threaded rods to get the spacing right.

Image

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Don
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Re: Another ESL Project... the psychosis continues

Post by Don » Mon Mar 14, 2016 6:11 pm

Looking good Charlie.
8)
To argue with a person who has renounced the use of reason is like administering medicine to the dead.
— Thomas Paine


"Try not to become a man of success, but rather a man of value" Albert Einstein

"Politicians are the only people in the world who create problems and then campaign against them". Charlie Reese

"The problems we face today exist because the people who work for a living are outnumbered by those who vote for a living." Brad Shurett


"Kindness is a language that the Deaf can hear and the Blind can see." Mark Twain

RIP BILL D. RIP WRABBIT

BobSmi57
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Re: Another ESL Project... the psychosis continues

Post by BobSmi57 » Tue Mar 15, 2016 6:18 pm

Wow, Charlie. That's a lot of work. Thanks for posting. Looks great.

Jazzman53
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Re: Another ESL Project... the psychosis continues

Post by Jazzman53 » Wed Mar 16, 2016 3:31 pm

OK... more porn for the pervs:

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oldtexasdog
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Re: Another ESL Project... the psychosis continues

Post by oldtexasdog » Sat Mar 19, 2016 4:02 pm

Good Lord Almighty! The patience alone is a mind boggle! Beautiful workmanship!!
There are two holes in Daddy's head where all the money goes.

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radioeng2
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Re: Another ESL Project... the psychosis continues

Post by radioeng2 » Mon Mar 21, 2016 1:59 pm

Image
I was there "At the Fest!" Hope you were too!

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