TWEESL 2020: an electrostatic tweeter with electrically delayed concentric rings - diyAudio
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Old 21st November 2012, 11:38 PM   #1
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Join Date: Jan 2004
Location: Silicon Valley, California
Default TWEESL 2020: an electrostatic tweeter with electrically delayed concentric rings

PR Dept: Andersonix Industries' numerous departments are all abuzz about introducing the DIY audio community to the TWEESL 2020 concept.

Ancient History Dept: Re-inventing the wheel/ Nothing new under the sun (see attached gifs of 1979 Peter Walker AES talk). Why hasn't this configuration at the tweeter scale seen daylight before now? I'm imagining that all the commercial ESL companies have tried this in their labs but abandoned it for some reason.

Recent History Dept: During BA2012 it finally sunk in that Siegfried Linkwitz's objection to the Quad ESL-63 is that the center ring is still too large to prevent beaming at higher frequencies.

Marketing Dept:
- Tweesl was initially conceived as an 'ESL ambassador' or 'missing link' to introduce cone speaker users to the ESL principle and as an 'SL-approved' dome tweeter replacement for Orion at half the cost of the Millenium tweeters.
- Sized to replace the typical 1 inch dome tweeter for easy PnP
- Can also be used as headphones
- Envisioned as being driven by a custom combination HV amplifier / HV bias supply capable of dual duty as Tweesl speaker amp and Tweesl headphone amp

Sales Dept: Offer early adopters a package consisting of one custom stereo amplifier and 8 Tweesl units (2 for speakers, 2 for headphones, and 4 spares) for "under $750"

Engineering Dept: Tweesl will require a custom amplifier/ HV supply and close tolerance inductors in a passive delay line. I will ask Papa to think for 10 minutes about a suitable transistor design.
For this concept to become reality, many details will need to be worked out: number of segments, D/S spacing, materials, tension, connections, amplifier, etc.

Irony Dept: Andersonix is reasonably satisfied with line source ESL hybrids so far and has no actual need for Tweesl at this point.

Procrastination Dept: The groundwork for Tweesl is almost 90 years old, so Andersonix would be satisfied for Tweesl to see market before 2020. In the meantime the Tweesl 2020 concept will be left here to gestate in the capable and imaginative hands of the DIY audio community. Please steal this idea and run with it. Andersonix Design Dept will be available to supply CAD models and prints for future Tweesl updates and related DIY projects, so please help keep the discussion alive!

Cheers,
Andersonix
Attached Images
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File Type: gif aes633.gif (54.9 KB, 225 views)
File Type: jpg tweesl and tweeter.jpg (77.5 KB, 225 views)
File Type: jpg tweesl assy1 front1.jpg (80.5 KB, 223 views)
File Type: jpg tweesl assy1.jpg (64.4 KB, 72 views)
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Old 22nd November 2012, 06:09 AM   #2
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I was just thinking about this concept again few weeks ago !!
I have thought about this many times before.


jer

Last edited by geraldfryjr; 22nd November 2012 at 06:21 AM.
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Old 23rd November 2012, 02:57 AM   #3
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The concept of ESL concentric ring radiators for mid/tweeter was used by Metrum Acoustics.
The panels they sold for the DIY market used 6 rings and were useable down to 400Hz for their larger panel and 900Hz for the smaller. They used a resistor ladder network rather than LC delay lines. This results in apparent source size shrinking with increasing frequency. The achieved improvement in HF dispersion is nearly identical with either approach.

Unfortunately, looks like Metrum Acoustics no longer sells these panels...in fact no mention of ESLs anywhere on their website now.
I used to have some nice pics of their stators showing the rings, but can't seem to locate them now.
Do It Yourself - Electrostatic Speakers - Material: - Metrum Acoustics


Here is a Dutch link with some pics of a kit they sold.
Recensie_pagina2 Metrum Acoustics Syncope De techniek
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Old 23rd November 2012, 08:34 PM   #4
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Jer, was there anything in particular that prevented you from realizing your concept? I don't have any actual experience building an ESL yet, but with your and others' help with practical matters, perhaps this can be explored further?
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Old 23rd November 2012, 08:43 PM   #5
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Bolserst, thanks for the info on Metrum! I would love to see better pics.

From the second link, a Dec 2008 review of the Syncope kit, here's my summary:
350Hz XO. A complete Syncope kit includes two Scanspeak 15W8530K00 woofers, two SP-2113-S ring radiators, two controlled high-voltage units with high pass filter and a low-pass filter and connectors and silver wire. The only thing missing is wood, MDF, Corian, or other material to build a cabinet. A construction drawing is of course included. Syncope Hybrid kit per pair: 1699 Euros.

I'm going to assume the ESL is 13cm x 21cm...
Attached Images
File Type: jpg Metrum_Syncope_3_031208.jpg (103.4 KB, 73 views)
File Type: jpg Metrum_Syncope_7_031208.jpg (109.5 KB, 78 views)

Last edited by Andersonix; 23rd November 2012 at 08:45 PM.
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Old 26th November 2012, 05:20 PM   #6
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Hi !

The Tweesl 2020 is an interesting concept, but i suggest the design to be non circular.
Better would be oval or rectangular.
The delay lines should remain circular.
This to attenuate certain resonans frequency.
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Old 27th November 2012, 10:13 AM   #7
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Andersonix, I am finishing up my First electrically segmented mini panel now.

All that is left is to mount the Diaphragm and I will be testing it for the first time this week.
Then I have to get some resistors.

So far I have waited a week to let the stator coating cure.

It has been a slow project as if I go to hard at it then I get burned out and have to set it down for a while.

On top of this project I have been brainstorming ideas for a better drive system from transformer's to a small Direct drive amplifier and/or a good small conventional amp as my big ones are to cumbersome to deal with and are hooked up to my bigger system and guitar rig.

I have some chip amps That I have been wanting to finish and I think they will be great for this project.

During this last little break I have been working on small woofer system to use with it.
I still have my little Sony 5.25" woofers but I recently dug out an old Bose subwoofer that I have had for a long time and it has Two 5.5" in it that would be a better match for it I think in about a .25 to .5 cubic foot box.

After measuring the T/S parameters of the drivers the Sony's are badly mismatched to the box's they came in.
It is very typical of such and explains why I has such a hard time to get them to sound right by sealing up the port,

Small funds are my biggest set back as it has been for a while, maybe that will change this year just gotta stay positive is all.

Basically, I have been doing a lot of research on the concept of segmented stator's and how and why they work.

When I came up with my small panel I had ideas to make a compression type of driver out of a couple of dead gold plated CD's I may still though one together to see how it will sound.

But the resonance of a circular diaphragm was I bit of concern as well.
I like the idea of a oval shaped driver and I have even looked in to the possiblilty of the irregular shape of an egg as well.
I have have some headphone drivers that I had started that are oval.

Stator type and coating has been what has been kept me from finishing them until now.

My main concern is to break the low voltage barrier (+5KV) that is need for a small driver to have good performance and loudness compared to that of a much larger panel.
I did pretty good with the last one only it wasn't designed to handle the voltages I was giving it and it finally gave out.

I had found that I could easily get into and above 100db using about 10kv or more of bias with only a 10v to 15v peak signal into at least a 1:220 to 1:440 step up transformation ratio using just my cheapy AIWA amplifier.

I was able to get as high as 15v to 20v peak with this finicky little amp.
And as long as it was below 15v peak it was louder than to be comfortable to listen to and didn't shut down on me.

110db is well within reach and I have done more with my bigger amp.
You must remember that sound level drops 10db at 4 meters this is a big drop for my small room of only 18.5 feet deep, as I am about 14 feet away from the speakers.
Not to mention my listening tastes are not that of chamber music either.
However that does not mean that I don't enjoy it once in a while !!

I have had this concept in mind for many many years only it has taken me some time to get just this far as life's stupid mistakes (DUI's) had set me back a bit, But I am back on track now.
I don't mind sharing that side of my story in hopes that it will help others to not get in the binds it has caused me as it took about 5 years to catch up were I had left off in 2006 not counting the down time and costs.

I know I have just posted these pics in another thread but here is what i have so far.

The complete details of this build can be found here,

A Segmented Stator Desktop ESL

jer
Attached Images
File Type: jpg Ready for The Diaphragm.jpg (168.3 KB, 55 views)
File Type: jpg Ready for The Diaphragm no flash.jpg (148.0 KB, 41 views)
File Type: jpg Nice Shot Of The Rods.jpg (119.4 KB, 47 views)
File Type: jpg side view.jpg (53.2 KB, 39 views)
File Type: jpg Connection Side.jpg (47.6 KB, 40 views)
File Type: jpg Ready to Be Coated.jpg (101.0 KB, 45 views)

Last edited by geraldfryjr; 27th November 2012 at 10:21 AM.
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