Do you want to learn how to build a better ESL?

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In my opinion if we really want to learn how to build better electrostatic speakers then getting to the bottom is not an option but a requirement. There are too many unsubstantiated claims and dogma and blindly repeating (not accusing anyone in particular) going on, and it is my new year resolution to step up the plate and demand more.

Call it the 'ESL Myth Busting thread' :D

I would like to propose the following approach:

0. Identify an item (claim) that needs scrutinization
1. find a plausible explanation (model)
2. come up with (and possibly agree on) a test to verify the claim / model
3. perform the test (preferably more than one person) and share the data
4. interpret the results


Some tests will be cheap, fast and simple, others will require time, money, sweat, perseverance and sleepless nights. But in the end we will have learned something. Something that can be relied upon, serve as a reference in future discussions and most important guide us in the right direction.

Some people prefer to just leave it at 'voicing opinions' and discuss things to no end, and that's fine. In this thread you can expect your claims to be challenged and if you're not prepared to go all the way then walk away now.

This does not mean you are not allowed to think out loud. I encourage you to think freely, but if you do so make it clear. Don't state your thoughts as facts.

So who's in?
 
:deer: As an owner of ESLs, and a DIYer of a few sets of speakers including sealed (CB), ported (BR) and transmission line (TL) (and an expert at none of them, although more experienced with TLs) I am RELUCTANTLY in.

But... as a musician who has never (as of yet) heard ANY speaker that REVEALS as well as an ESL I am definitely in.

Expect my input to be (at first) of the very general sort,
ie; GENERAL questions and comments, but will try not to derail or uselessly complicate the thread to the best of my ability.

Great idea for a DIY thread, Cheers!
Steve
 
Great!

Now we will start to make a list of things we would like to confirm or bust :devilr:

First I'd like to declare: anything that has not been tested by us in a proper way, and is not completely obvious from solid ESL theory, qualifies as a Myth. So you can start right now by thinking about those things in your head that you think you 'know', but are actually myths. I will give an example.

Some time ago there was a discussion going on on DIYaudio. The question was if a diaphragm that is not exactly centered between the stators raises distortion or not.

I put that to the test in this thread.

Something else we all know from certain books and web sources is that a coating with a resistance of 1E7 is high enough. In the above mentioned thread the data showed that it is not, and we actually need a resistance of about 1E10. Myth busted.


Here are my suggestions for myths we can test:
  • non-uniform coating causes frequency anomalies, distortion and possibly resonances
  • optimal stator open percentage is around 40% (popular recommendation: 3mm holes with 4mm spacing is 51%). What are the compromises?
  • for an electromagnetic bass to match with an ESL it needs to be a dipole.. this is going to be a hard one

If you have any myths, suggestions, would like to take on one of these, let's hear it!
 
I am readind this thread, I am in, however I am no expert in this field, I am fasinated by the desighn os ESL and would love to learn more about the stator and the effects, like i said, I would like to learn. ClarlieM, has spoken with via phone, his stuff looks nice, so what about his achievemnts? His pics do denote dipole, but difusing the rear wave with the cabinet that he posted pics(links) of. Can anyone post pics of their projects here and as far as testing, what program will be the "contol" something everyone uses as a testing device?
 
Standard measuring

Hey Mavric, I have looked at Charlie's ESL build, and it looks great, but I also don't know how his "beam splitter" sounds, or how it effects overall ESL sound,

Anyways, I do agree that a standard measurement system should be established so we are working apples to apples.

A system like PRAXIS is great (which I use) but any of them is OK ie. LEAP CLIO etc. any one that is accepted as a true
measurement tool should be OK

Any comments?
Steve





Steve
 
Hi Arend-Jan,

May I propose that we do a test on the comparison of asymmetric alignment of the stator holes? I think this is where you left off a few months ago. It would be interesting to see the differences in efficiencies and distortions between the perfectly aligned stators versus the asymmetric ones.

Wachara C.
 
Hey Mavric, I have looked at Charlie's ESL build, and it looks great, but I also don't know how his "beam splitter" sounds, or how it effects overall ESL sound,

Anyways, I do agree that a standard measurement system should be established so we are working apples to apples.

A system like PRAXIS is great (which I use) but any of them is OK ie. LEAP CLIO etc. any one that is accepted as a true
measurement tool should be OK

Any comments?
Steve

I was curious about the effects of the beam splitter myself so some months ago I took one of the stat panels out and placed it in free air beside the cabinet (next to the woofer). It sounded different but neither better nor worse-- no discernible difference in clarity or definition that I could tell, just a different ambience that I suspect had to do with the backwave having a different path to the nearest walls before reflecting back to my ears from different angles and distances than before. I was relieved that I did not hear an appreciable downside to the beam splitter. Of course, my impressions are totally subjective, since I have no equipment to make any objective measurements. I would probably not ever build two sets of speakers the same way (always wanting to try something different). If I were to build another set of hybrid ESL's , I would probably build something similar to Roger Sanders' newest hybrids, which use a really nifty compact transmission line bass with the woofer under the stat panel but it's not a beam splitter.

Mavric, I'm only an hour's drive from Statesboro and you are invited to drop by for a listen any old time. In any case, best of luck with your project.
 
Hi Arend-Jan,

May I propose that we do a test on the comparison of asymmetric alignment of the stator holes? I think this is where you left off a few months ago. It would be interesting to see the differences in efficiencies and distortions between the perfectly aligned stators versus the asymmetric ones.

Hi Wachara,

A perfect candidate indeed. I did this test but could not get meaningful results. Perhaps the difference is insignificant, but I will visit it again.
 
Designing speakers is about making compromises. To do so we first have to understand those compromises. For example hole spacing in stators, are you going for 30,40,50,60%? And why? Because someone else did it that way? This thread is not about 'I would copy XYZ design' but finding out which parameters matter and which don't. And if they do matter what are the consequences of choosing A over B. That way we can make an informed decision.

With this knowledge you can make your own design. And you may end up using the 'proven' values that are the norm, but at least you will know that they are optimal for your design.

When I look at the multi way speaker forum (for example in the 'beyond the ariel' thread) I see a discussion on a higher level, where people challenge each other and present measurement data to back up their statements. That's what I would like to see for this planar forum. Get a bit more science into it.
 

My hat's off to JonasKarud for the unique innovations I see in his speakers. I had to disassemble and rebuild a stat panel once when a weak spot of insulation along a stator edge arc'd and shorted out the panel. I'm thinking how easy that task would have been (as opposed to the nightmare it was) had I assembled the panels using magnetic spacers rather than UHB foam tape (or glued spacers). GREAT IDEA Jonas!
 
Measurement question

When I look at the multi way speaker forum (for example in the 'beyond the ariel' thread) I see a discussion on a higher level, where people challenge each other and present measurement data to back up their statements. That's what I would like to see for this planar forum. Get a bit more science into it.[/QUOTE]

Fair enough, but getting back to what measurement software should be acceptable if someone should want to "delve in" that far, Is Speaker Workshop considered acceptable being freeware and all? From what I have read only the distortion measurements don't take into account the distortion of the sound card itself, AGAIN, any comments?

Cheers, Steve
 
I too would like to know the optimal % open area and hole size for perforated stators. Unfortunately I am neither equipped nor prepared to contribute any measurements to that end.

At the risk of getting off subject, I will add:
For those like myself who are not so knowledgeable and experienced, perhaps the single most daunting impediment to building ESL's is finding a suitable and affordable step up transformer that's available in the US. In these hard economic times especially, most of us can't spring for Aplimo's or Plitrons.

Calvin has posted some great threads showing good results with cheap tandem 230v/6v European power toroids; however, those type toroids (230v with single windings flash tested to 4KV) are not available in the US. I searched the web for months without finding a US source or a European source that would accept dollars and ship to the US.

If someone could just specify a reasonably good performing, inexpensive and readily available step up transformer setup, I think that would do more to help newbies build ESL's than anything else.
 
I too would like to know the optimal % open area and hole size for perforated stators. Unfortunately I am neither equipped nor prepared to contribute any measurements to that end.

At the risk of getting off subject, I will add:
For those like myself who are not so knowledgeable and experienced, perhaps the single most daunting impediment to building ESL's is finding a suitable and affordable step up transformer that's available in the US. In these hard economic times especially, most of us can't spring for Aplimo's or Plitrons.

Calvin has posted some great threads showing good results with cheap tandem 230v/6v European power toroids; however, those type toroids (230v with single windings flash tested to 4KV) are not available in the US. I searched the web for months without finding a US source or a European source that would accept dollars and ship to the US.

If someone could just specify a reasonably good performing, inexpensive and readily available step up transformer setup, I think that would do more to help newbies build ESL's than anything else.
 
I too would like to know the optimal % open area and hole size for perforated stators. Unfortunately I am neither equipped nor prepared to contribute any measurements to that end.

At the risk of getting off subject, I will add:
For those like myself who are not so knowledgeable and experienced, perhaps the single most daunting impediment to building ESL's is finding a suitable and affordable step up transformer that's available in the US. In these hard economic times especially, most of us can't spring for Aplimo's or Plitrons.

Calvin has posted some great threads showing good results with cheap tandem 230v/6v European power toroids; however, those type toroids (230v with single windings flash tested to 4KV) are not available in the US. I searched the web for months without finding a US source or a European source that would accept dollars and ship to the US.

If someone could just specify a reasonably good performing, inexpensive and readily available step up transformer setup, I think that would do more to help newbies build ESL's than anything else.
Have you tried digi-key? They do sell medical grade transformers...
Talema/Alfamag used to have good toroids as well
Alex
 

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Thanks, CharlieM.

The optimal open area is, according to a white paper from researchers at Panasonic, 42%.

However, the graph in the paper shows that anything between 30 to 60% will do.

This is for a theoretical transducer without insulating stator coatings and it is the lower Velocity curve you shall look at. The X-axis represents the open area, Beta. The speaker in this case has an electret membrane, but the physics are the same, I think.
 

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