Electrostatic speakers?

[Blumlein 88]

I had some Acoustat Two speakers which were very beamy. 5.5 feet (1.67 meters) from the rear wall, sitting 10 ft (3 meters) from them with a spacing of 12 ft (10.9 meters). My sofa was in the best listening spot. Middle seat, good, good stereo. Right seat or left seat heard very nearly only the right or left speaker. Depending upon where the axis of them crossed those on either side might hear only the channel on their side. When I had friends over I put a chair in front of and behind the sofa so three of us had stereo.

 

[dasdoing]

When I had friends over I put a chair in front of and behind the sofa so three of us had stereo.

makes much more sense anyways

 

[dlaloum]

I don't have that much room nor do most people.

That is the main issue with ESL's!!

 

[dlaloum]

One remark about the ESL57, I see people connect all sorts of amps to them and I think that is a bad idea. Yes it's easy to damage an electrostat but that became quickly apparent with the ESL57 and almost all but the first series now have an extra circuit that protects the treble panels. There was a retrofit for the first models and I would expect a restored model would be fitted with it.

Also, the amp of choice for these speakers is the Quad 303 that is more or less designed to drive ESL57's. It can deal perfectly with the weird impedance curve and it is limited to 30 Volts. I regularly see these amps still offered for quite reasonable prices. Granted, it is rated for only 2x15Watts but that is plenty for the ESL57, more is overkill(!) anyway.

They blend perfectly with dipole subwoofers like Ripoles, I can certainly enjoy the infamous "Funkenspelunkin" but indeed with dipole woofers you don't need to replace all the crockery in the cupboards and since I live in an apartment, I don't have a crowd of neighbours brandishing torches and pitchforks outside my front door.

As with every kind of dipole, they do need room to breathe. The layout of my apartment allows me to place them with large spaces behind them and that may not be possible everywhere. And they do have that "head in a vice" sweet spot, but the sound quality is acceptable for casual listening outside that sweet spot. If I then really want to listen to an album, the sweet spot is perfect. I don't see the point of "perfect sound in the kitchen" as I have other things to focus on in there anyway.

The ESL57 was originally designed as a mono speaker "offering a window on the stage as seen from the balcony". That does not work for stereo in a modern living room and allegedly Peter Walker recommended to "place them on a beer case". The dimensions of 2x12" Ripoles certainly come close to that!!

View attachment 365220

Actually placing the ESL57 as in the promo picture will make sure it doesn't sound any better than a small portable radio but that carpet would drive me nuts anyway.

Incidentally my ESL57's were found in a thrift store by my girlfriend "Look at those funny vintage looking things there." When I heard the EUR 500 price tag I had to pick up my jaw from the floor again. I will get them restored some time but for the moment they are still fine.

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Saying that the 303 is "overkill" is an understatement - going a volt or two over the speakers very stringent limit will cause visible arcing (assuming you are in a darkened room) - and once they panel is damaged by arcing, that voltage limit reduces quite stringently, resulting in higher probability of arcing, and each subsequent incident makes things worse... hence they can easily self destruct... ie: they "kill" themselves...

I have a pair in storage along with a 303....

I would strongly urge people NOT to try to drive a set of 57's with any form of "overkill" amps.... habits that with standard speakers, are harmless, with 57's can quickly result in needed a panel rebuild.

Treat with care and respect, and they can truly do magic....

 

[Blumlein 88]

I built an led indicator when I had 57s. Using a zener diode to turn on at a conservative safe voltage. So you would see it light if you got close. This was just to use until I had the proper sized amp.

 

[Axo1989]

This has been discussed numerous times, and it is not the correct interpretation of the relatively bunched up stereo preference scores.

I am confident that you and Axo have both come across these prior discussions, yes?

I am not sure why people are sticking to this mistake, unless it is the usual problem: "It doesn't comply with my sighted listening impressions".

I'm not sure if that's a straw man, or genuine misread. I noted difference between loudspeaker preferences based on playback material. And mentioned stereo vs mono in passing (which you look like you misinterpret again, but that has no bearing on the point of the post). There was no mention of uncontrolled vs controlled (aka sighted vs blind) listening so this has no bearing on the point of my post either.

 

[gnarly]

Apologies if it looked like it was all ‘me vs you’.

cheers

Thanks for a gracious reply. My apologies too, if i came on too strong...
cheers indeed !

 

[Newman]

The correct interpretation is: the speakers aren't "doing better" in stereo, it's just that the test is "doing worse". ie the stereo test isn't a good enough test to tell us anything about whether the speakers are "doing better" or not.

Why? The change in preference score changed much more for the Quads in stereo across the board. Stereo is the common usage. How is the test “doing worse?” What unique circumstance in stereo with the Quads causes the test to “do worse?”

It's not about the Quads, it's about the test. Toole didn't publish that graph to tell us something about the Quads: he published it to tell us something about the limitations of stereo as a loudspeaker preference rating test.

Links to my previous comments on this point, 1, 2, 3

Toole endorsed my view that "We can’t actually say the Quad improved its sense of space at all, while the data is suggesting that the test is not an appropriate test for that attribute."

 

[Justdafactsmaam]

It's not about the Quads, it's about the test. Toole didn't publish that graph to tell us something about the Quads: he published it to tell us something about the limitations of stereo as a loudspeaker preference rating test.

Links to my previous comments on this point, 1, 2, 3

Toole endorsed my view that "We can’t actually say the Quad improved its sense of space at all, while the data is suggesting that the test is not an appropriate test for that attribute."

Let me start by saying speakers should be measured and tested in mono.

However…if this test demonstrates the limitations of a test it’s the listening test in mono that is being demonstrated to be limited.

Quads are generally used in stereo. If they test better in stereo than in mono in a way that box speakers do not then the test in mono alone is failing to reveal this atypical quality in the Quads. And it follows that testing the Quads in mono alone will not reveal their real world performance in stereo.

 

[dlaloum]

Let me start by saying speakers should be measured and tested in mono.

However…if this test demonstrates the limitations of a test it’s the listening test in mono that is being demonstrated to be limited.

Quads are generally used in stereo. If they test better in stereo than in mono in a way that box speakers do not then the test in mono alone is failing to reveal this atypical quality in the Quads. And it follows that testing the Quads in mono alone will not reveal their real world performance in stereo.

The results on the Quads clearly indicated a flaw in the tests with regards to the behaviour of bipole/dipole type speakers, and the way in which they project sound into a room differently to the manner that unipolar box speakers do...

That flaw is probably related to the test room... - bipole/dipole speakers are intentionally made that way - they use the rear soundwaves, reflected off the back and side walls intentionally (and yes there are ESL designs that absorb the rear emissions like "standard" speakers do - which then tend to behave much like "box " speakers ... and also tend to look more like boxes rather than panels!)

Peter Walker, was a pretty pragmatic kind of engineer/designer, and designed his speakers to be used within certain kinds of listening environments ... The 57's do have padding at the rear to provide partial absorbance.... - the 63's (and their descendants) don't... their designed for different environments.

 

[Newman]

Quads are generally used in stereo. If they test better in stereo than in mono in a way that box speakers do not...

Your conclusion has not been supported by the evidence. However, your misinterpretation of the mono vs stereo results is very common. Your conclusion seems logical if, and only if, the stereo test is of sufficient experimental quality to draw conclusions. But it simply isn't of such quality.

Let me promise you this: if that test was evidence that stereo listening was needed to determine attributes of loudspeaker preference that mono listening cannot reveal (which one might think, at first glance), then Toole would see that too, and he would have concluded that loudspeaker preference ratings cannot be determined without a stereo listening contribution. But it doesn't tell us that, and Toole didn't conclude that. Toole literally asked in his book, in discussion of the mono/stereo tests, "Did stereo reveal a capability that could not be heard in mono?" He concluded that it did not. So I don't see how you can conclude that it did.

 

[Justdafactsmaam]

The results on the Quads clearly indicated a flaw in the tests with regards to the behaviour of bipole/dipole type speakers, and the way in which they project sound into a room differently to the manner that unipolar box speakers do...

That flaw is probably related to the test room... - bipole/dipole speakers are intentionally made that way - they use the rear soundwaves, reflected off the back and side walls intentionally (and yes there are ESL designs that absorb the rear emissions like "standard" speakers do - which then tend to behave much like "box " speakers ... and also tend to look more like boxes rather than panels!)

Peter Walker, was a pretty pragmatic kind of engineer/designer, and designed his speakers to be used within certain kinds of listening environments ... The 57's do have padding at the rear to provide partial absorbance.... - the 63's (and their descendants) don't... their designed for different environments.

Not all dipoles. Roger Sanders uses his own speakers in a garage with the front wall/garage door open. His speakers are designed to interact as little as possible with the room and sound their best in rooms with minimal reflections

 

[misterdog]

The 57's do have padding at the rear to provide partial absorbance.... - the 63's (and their descendants) don't... their designed for different environments.

But they do, there is a very thin mesh on the rear stators of all > 63 panels..

 

[dasdoing]

If you test speakers in mono, you need to take the room out of the equation, else wider dispersion will always win

 

[Duke]

I agree that most ESLs have a distance from the wall they like. Most seem to be around 5 to 6 feet.

I don't have that much room nor do most people.

That is the main issue with ESL's!!

5 to 6 feet is the distance-from-the-wall recommendation I arrived at experimentally many years ago, and later I met Earl Geddes and began reading David Griesinger, and they both recommend 10 milliseconds reflection-free interval after the arrival of the direct sound, which corresponds to the time it takes for the backwave to arrive after bouncing off a wall 5.5 feet behind the panels. (With most dipole electrostats, the effective reflection-path-length distance would be increased if the speakers are toed-in significantly).

About fifteen years ago I started to incorporate rear-firing tweeters in my own speaker design, which imposed a reflection-path-length requirement that called for positioning the speakers fairly far out from the wall. I didn't want to impose this requirement on my customers so I started aiming the rear-firing tweeter either upwards or up-and-back at an angle, which resulted in a considerably longer reflection path length. Imo it seems to work - it seems to give the intended benefits while allowing the speakers to be placed much closer to the wall than would normally be acceptable.

This leads me to wonder whether a large enough waveguide could re-direct the backwave of an electrostat in a way that allows closer-to-the-wall placement than we can normally get away with. Harold Beveridge used waveguides in his (imo brilliant) electrostat designs, but he used them for the frontwave. Unfortunately a dedicated backwave waveguide would increase the "visual mass" of the speaker considerably, even though the net result might be less real estate being effectively occupied by the speakers.

 

[misterdog]

I don't have that much room nor do most people.

Hence why they invented electrostatic headphones

 

[Justdafactsmaam]

Hence why they invented electrostatic headphones

These may be the answer https://janszenaudio.com/

 

[misterdog]

These may be the answer https://janszenaudio.com/

No.

 

[Justdafactsmaam]

No.

I’m going to go with yes.

“Not being dipoles, they have no back wave, which makes them as easy to set up as ordinary speakers. In fact, the relatively high room independence makes it easier than most.”

 

[misterdog]

They have a box for a magnetically driven woofer.
They have a crossover to control the signal between panel and woofer.
They have small panels.

It's marketing hype trying to sell the magic of panels in a small form factor to the 'audiophile' market.

I had Martin Logan Electromotion speakers in the same room as my Quads, One pair looked great and one pair looked like doors.

More importantly though one pair sounded magical and one pair sounded as though they were trying to achieve mediocrity.


The ElectroMotion ESL represents a bold new direction for electrostatic loudspeaker design. Featuring a full-sized 34-inch tall curvilinear XStat™ electrostatic transducer and a superbly integrated high-performance woofer, the new EM-ESL performs more like a mini-flagship than an entry level audiophile speaker. Designed for both 2-channel music enthusiasts and those seeking the worlds most articulate and dynamic multi-channel home theater systems, the EM-ESL is the most compelling 'affordable' audiophile-grade speaker ever brought to market.

The ML's looked great- sounded shite.