Electrostatic speakers?

[dlaloum]

I'm always curious what ESL's sound like, I've never gotten the chance to hear a set, but knowing some measurements would help me get an understanding of what they should "kinda" sounds like. Would you describe ESL's as having wide or narrow directivity? Ive always wondered why Martin Logans are curved and why some ESLs are Flat, and why most of them seem to be Open Back/Baffle but only Janszen ones are sealed. Is there any pros and cons of each and why more companies don't enclose them?

Like any type of speakers, the electrostatic can be made in a wide or narrow directivity.....

The Quad ESL63 and its descendants use delay lines in the panels, to simulate a pulsing ball of sound about a meter behind the speaker - and the combination of reflected sound from the rear, and direct sound from the front gives a wide directivity pattern.

Its predecessor the ESL57 is a very narrow directivity design - it's purity in the midrange is rightfully legendary (and many speaker designers have kept a pair as a reference for the midrange alone!) - but it does tend towards a one seat "sweet spot".

So there are various solutions (including the curved ML designs) - and various compromises - but they are different to the compromises and solutions used with "cones and magnets"

 

[lewdish]

Like any type of speakers, the electrostatic can be made in a wide or narrow directivity.....

The Quad ESL63 and its descendants use delay lines in the panels, to simulate a pulsing ball of sound about a meter behind the speaker - and the combination of reflected sound from the rear, and direct sound from the front gives a wide directivity pattern.

Its predecessor the ESL57 is a very narrow directivity design - it's purity in the midrange is rightfully legendary (and many speaker designers have kept a pair as a reference for the midrange alone!) - but it does tend towards a one seat "sweet spot".

So there are various solutions (including the curved ML designs) - and various compromises - but they are different to the compromises and solutions used with "cones and magnets"

That's great to know Didn't know you could actually control the wave form of ESL's like that. But wouldnt the rear reflected sounds also have various delays from the room causing filtering of sorts?

 

[Gwreck]

I'm always curious what ESL's sound like, I've never gotten the chance to hear a set, but knowing some measurements would help me get an understanding of what they should "kinda" sounds like. Would you describe ESL's as having wide or narrow directivity? Ive always wondered why Martin Logans are curved and why some ESLs are Flat, and why most of them seem to be Open Back/Baffle but only Janszen ones are sealed. Is there any pros and cons of each and why more companies don't enclose them?

The curved panel is meant to widen their directivity as they tend to
Have a very narrow directivity. I own Sanders ESL’s and they are the most narrow directivity speakers one can buy AFAIK. The narrow directivity helps to minimize room interaction. They are not great for hometheater due to this as they are one person speakers. Martin Logan’s have somewhat wider directivity but still are narrow.

A good set of EsL’s has strong imagining and they can have an almost surround sound effect putting sound outside of speakers. They sound more “forward” to me and images can be clearly in front of the speakers and even directly in your ears.

 

[traind]

I'm always curious what ESL's sound like, I've never gotten the chance to hear a set, but knowing some measurements would help me get an understanding of what they should "kinda" sounds like. Would you describe ESL's as having wide or narrow directivity? Ive always wondered why Martin Logans are curved and why some ESLs are Flat, and why most of them seem to be Open Back/Baffle but only Janszen ones are sealed. Is there any pros and cons of each and why more companies don't enclose them?

I think it's worth it to hunt down a store either somewhere near you or while on a trip to hear electrostats just to see why many adore them.

I am in the market for another set of speakers and have explored Martin Logan' ESLs on several occasions now. I listened to a set of used ESL 15As at a store that did not sell the brand new but the owner apparently had them set up very well. The soundstage width and separation was perhaps the best I have ever heard from any speaker when in the central chair. Move one chair over and it diminished, still good mind you, but not the revelation as it was in the sweet spot. A set of 13As set up less meticulously but in a good room did not impress quite as much but I still found them excellent. In that room I got up and moved around and the sound remained very good. Yes, it changed some but not terribly to my ears. I think perhaps I was not ever in the sweet spot in that room so it sounded very good but never quite as magical of a soundstage as the used 15As.

The other great thing is voices. Wow, when set up well it sounds like the artist is right there in the room with you. There is just another quality about them that has an impact on vocals that make you want to buy a pair just for that lol. I have heard that on multiple occasions with ML ESLs. I do think they need space to be their best and that is what holds me back from buying a pair as my rooms are not large. It is certainly not the sound quality that holds me back. And I think it's cool that you get some real standout features to sound quality if you buy them. I did listen to a pair of 15As in Denver that were in the same room as a pair of Blade 1 Metas. I think the setup of the Blades in the room was advantageous because they had more space between them than the ESLs but it was an interesting comparison nonetheless. Vocals sounded better on the ESLs to my ear but I would give the win to the Blades overall.

 

[dlaloum]

That's great to know Didn't know you could actually control the wave form of ESL's like that. But wouldnt the rear reflected sounds also have various delays from the room causing filtering of sorts?

Yes - which is why stats have their own particularities with room positioning, space, etc.... (I'm talking about dipole stats) - they need some distance from walls behind them, they are not so sensitive to side walls (as there is little output sideways!)

A meter or two behind them, with some curtains is usually all that is needed - the curtains pick up the high frequencies, and the distance ensures that the lows don't cancel out and interact in a nasty way.

 

[kevin gilmore]

i gave away a refurbished pair of esl63's about a month ago. they started buzzing, so they were free to the buyer.
always great sound. no bass. and they won't play loud. but if you ever got the privledge of seeing peter walker demo them
where he was showing that they made virtually perfect square waves... no other speaker i know of can do that.

electrostats are a pain. electrostatic headphones are an even bigger pain.

 

[Audio Science Pal]

I enjoy my Martin-Logan speakers.

 

[egellings]

I'm always curious what ESL's sound like, I've never gotten the chance to hear a set, but knowing some measurements would help me get an understanding of what they should "kinda" sounds like. Would you describe ESL's as having wide or narrow directivity? Ive always wondered why Martin Logans are curved and why some ESLs are Flat, and why most of them seem to be Open Back/Baffle but only Janszen ones are sealed. Is there any pros and cons of each and why more companies don't enclose them?

My impression of ESL's is that flat ones are very beamy; step off to the side of one just a bit and the highs disappear. Curved ones may prevent that. I've never heard a curved ESL, so I don't experientially know.

 

[Jazzman53]

I'm always curious what ESL's sound like, I've never gotten the chance to hear a set, but knowing some measurements would help me get an understanding of what they should "kinda" sounds like. Would you describe ESL's as having wide or narrow directivity? Ive always wondered why Martin Logans are curved and why some ESLs are Flat, and why most of them seem to be Open Back/Baffle but only Janszen ones are sealed. Is there any pros and cons of each and why more companies don't enclose them?

There's really no way to adequately describe the ESL sound, but no conventional driver I've heard can match an ESL's mid-range resolution. For me; hearing an ESL for the first time was analogous to seeing a 4k video on an OLED TV for the first time -- amazing!

I don't have any means to plot graphs for you but I'm sure you could dig some up on the web-- an impulse response graph (square-wave) from an ESL would be particularly impressive.

Mono-polar (sealed) or dipolar?
I haven't heard the newer Janzen hybrid ESLs which have the panel mounted in a sealed box. The diaphragm would respond to any standing waves bouncing around inside the box to bad effect, so I'm curious about what materials were used to absorb the backwave radiation, and how they tamed it. The Janzen's get great reviews so I assume they figured it out, and I speculate that it would sound like most other high quality mono-pole speakers but with exceptionally good midrange resolution.

I may change my mind if I ever hear the Janzens, but I like the abience of my dipolar ESLs, and conceptually I'm thinking dipolar would more closely mimic the multi-directonal sound emitted by musical instruments and voices-- even if dipoles makes speaker placement more challenging.

Directivity:
I would say that most ESLs, even those with curved panels, project a narrower sweet spot, as compared to most conventional speakers. The big Sound Lab's would probably project a wider sweet spot than other ESLs by virtue of their wider curved panels.

I've never heard the Quad 63 and similar designs so I can only speculate. Based on their segmentation/delay-line scheme, I deduce that they would likely have pretty good dispersion.

Narrow dispersion/directivity isn't necessarily a bad thing, though. In fact; non-segmented flat panel ESLs like Roger Sanders' speakers are purposely designed to be highly directive-- because flat panels provide imaging and slam (at their tightly-focused sweet spot) that you just can't get from a wider-dispersion speaker. The Sanders speakers priorotize imaging over dispersion-- great for solo listening but not so much for entertaining guests.

I built unsegmented flat panels for years so I know exactly what they sound like, and believe me; if you've never sat at the focus of a pair of flat-panel ESLs, you can't fully imagine how ultra-directional they are, or how magical their imaging is. But there's no free lunch-- the speaker would have been tuned for balanced response at the focus, and because it's so directional, if you move your head even one foot outiside the tightly focused sweet spot the highs fall off a cliff, and much of the magial imaging is lost. Some refer to this as the "head-in-a-vise" effect. If you move far enough out of the sweet spot, reflections off the room walls average out the response and it sounds fine but lacks the magical imaging experienced at the focus.

Segmentation:
Then there are flat panel ESLs which employ electrical segmentation to curve the wavefront. This approach can tailor the dispersion pattern from narrow to wide or anywhere in-between by varying the number, widths, and symmetry of the separate stator segments.

Segmentation adds complexity and labor, so the few commercial ESLs that use it typically settle for 'good enough', and add a single narrow segment to spread the highs, or separate segments for mids and highs for a bit smoother-trending dispersion.

Some DIY designs (being less constrained by labor cost) use many narrow segments, as many/narrower segments give wider, smoother-trending dispersion.

My own DIY flat panel ESLs are symmetrically segmented using (15) six-wire groups-- consisting of (1) wire group on the panel centerline, and (7) left/right paired wire groups arranged on either side (7 + 1 + 7 symmetry). This arrangement works amazingly well.

FYI: Below are directivity sonograms posted by Steve Bolser on the DIY Audio Forum, comparing an unsegmented flat panel, a 30-degree curved panel ESL, and a segmented flat panel:

Jazz

 

[30 Ounce]

I’ve had MartinLogan CLS II’s since about 1989. I’ve had them in several rooms over the years and can attest to their demand for careful setup. They almost require a dedicated space. While the curved panels may help with dispersion I find that comb filtering is still present and slight head movements can alter the sound. When set up properly they will present a soundstage that is so realistic that it defies all logic. I’ve had them produce sounds behind my head that are so solid a realistic that it makes me look behind me to make sure nobody snuck up on me. Sometimes sounds seem to develop 6 inches to my left ear or right ear. They are truly amazing. Unfortunately their size has outgrown my wife’s patients and although I still have a dedicated listening room I have had to downsize my speakers and they have been in storage for a few years.

 

[Jazzman53]

I’ve had MartinLogan CLS II’s since about 1989. I’ve had them in several rooms over the years and can attest to their demand for careful setup. They almost require a dedicated space. While the curved panels may help with dispersion I find that comb filtering is still present and slight head movements can alter the sound. When set up properly they will present a soundstage that is so realistic that it defies all logic. I’ve had them produce sounds behind my head that are so solid a realistic that it makes me look behind me to make sure nobody snuck up on me. Sometimes sounds seem to develop 6 inches to my left ear or right ear. They are truly amazing. Unfortunately their size has outgrown my wife’s patients and although I still have a dedicated listening room I have had to downsize my speakers and they have been in storage for a few years.

I too had the wife approval issue to deal with but I finally got that resolved-- I don't even miss her

 

[Snarfie]

I’ve had MartinLogan CLS II’s since about 1989. I’ve had them in several rooms over the years and can attest to their demand for careful setup. They almost require a dedicated space. While the curved panels may help with dispersion I find that comb filtering is still present and slight head movements can alter the sound. When set up properly they will present a soundstage that is so realistic that it defies all logic. I’ve had them produce sounds behind my head that are so solid a realistic that it makes me look behind me to make sure nobody snuck up on me. Sometimes sounds seem to develop 6 inches to my left ear or right ear. They are truly amazing. Unfortunately their size has outgrown my wife’s patients and although I still have a dedicated listening room I have had to downsize my speakers and they have been in storage for a few years.

How are the lows.

 

[Gwreck]

I have Sanders ESL’s and there are definitely reasons why one would choose narrow directivity speakers over wide dispersion speakers despite the common belief that board dispersion is the best. Roger Sanders who is not to be confused with Gayle Sanders of Martin Logan has multiple white papers and a pretty good white paper on dispersion on his website. He actually invented the curved esl panel that Martin Logan uses but came to the conclusion that it had too many drawbacks and he prefer flat panels.

Sanders Sound Systems - Technical White Papers

Electrostatic specialists for Electrostatic Loudspeakers (ESLs) along with our Magtech and ESL amplifiers.

www.sanderssoundsystems.com

 

[30 Ounce]

How are the lows.

I’ve always had subwoofers. Originally Entec (which I rebuilt a couple years ago) and then a pair of Velodyne HGS15’s. I crossed them over at around 40 hz and let the panels run full range. They do a credible job down to about 40-50 hz if placed in the room properly. The most stunning reproduction of upright bass was with this setup.

 

[Fidji]

How are the lows.

I have had 3 generations of ML’s [Sequel/Summit/15A] and the most audible improvement between generations was in the bass-to-panel integration.

15A’s [and other Masterpiece series] have dual woofers front and back and active bass section with DRC ability [Anthem ARC] that works pretty well, 15a’s have 2x500W in each speaker and double 12in woofer. In-room down to 18Hz. There are also adjustment opportunities for bass section to tailor output to the room. Big sound with lot of punch if called for.

Probably it is repeating theme in 46 pages of this thread, but they really benefit from careful placement and from acoustic treatment optimized to their dispersion pattern and they require lot of clearnace from front and side walls. Not so demanding on floor/ceiling.

Meanwhile I am so used to eletrostatic sound that in most of the speakers I can “hear” the tweeter.

EDIT: photo added - I find them actually visually unobtrusive and my wife likes the looks.

 

[misterdog]

Quad 989's here, chucked away the sub optimal frames and fitted the panels into steel box frames filled with cat litter.
Raised the panels so the centre of the panel is at ear level (Quad use a 3 degree tilt back with the feet, to try to achieve that)

I now have speakers the size of a door.

I now have sound that I could only dream of when a teenager.

They benefit from the lowest possible distortion feed chain, currently using Topping B200 Mono's, previously used Benchmark AHB2 and Hypex N-Cores.

When used as home theatre the stage is bigger than the room.

Bass is ample, though 2 x 12" open baffle dipole subs provide the lowest octave and the chest punch which so many desire.
989's are run full range, subs are run up to 60Hz using MiniDSP plate amp, which allows for full control from laptop at the seated position.

Less fed distortion gives better bass, solid steel frames and no dust/protection covers gives better bass.

End game for me.

 

[Newman]

This thread has leapt back to life and the myth masters seem to be having their way with it all over again.

 

[Soandso]

…good set of EsL’s has strong imagining and they can have an almost surround sound effect putting sound outside of speakers. They sound more “forward” to me and images can be clearly in front of the speakers and even directly in your ears.

According to Jens Blauert's 1969 research we perceive sound from our midline (nose to back of skull) orientation no matter where the sound is coming from a bit differently depending on the sound frequency we are exposed to. As graphed in the screen shot chart below around 300-500 Hz, and again 3,000 Hz we perceive that as in front of us. While sound peaking at 1,000 Hz and again likewise at 10,000 Hz we perceive that as in back of us. And lastly peaking sharply 1,000 Hz sound we perceive as being atop us.

This would explain your sense of being surrounded with sound from electrostatic speakers and when summed together envelop your head cresting the impression it came in your ears. My premise being the electrostatic's relative speed produces exceptionally clear audio frequencies which facilitates our evolutionary disposition for attention of content in sound clues. Other facets than this inter-relationship to bands of frequency co-evolved to perceive where the sound is coming from (locate) and distance (loud) in the direction of the sound source.

Note: I assume the below graph is of some average test subjects' data and individual human variation(s) surely exist. So I am not declaring it represents fixed ranges - allow me to present this as patterns to consider.

 

[misterdog]

This thread has leapt back to life and the myth masters seem to be having their way with it all over again.

Here's some stats for you to debate then.

Quad ESL loudspeakers are known for very low distortion figures, especially at moderate listening levels.
Distortion (100dB at 1m): Above 1kHz 0.15%, above 100Hz 0.5%, above 50Hz 1.0%

 

[Newman]

I don't debate facts, I debate myths.

Although some facts are interpreted in ways that turn out to be myths!