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Electrostatic speakers?

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I have not been following this thread so if this has been brought up my apologies. But I will relate what happened to a friend of mine.

He built a pair of Electrostatic speakers with integrated transformerless (iirc) tube amp, that appeared in the Audio Amateur. They sounded quite good.
Later he and his wife moved away but I had a business trip and visited them. The Electrostats were gone replaced with some panels similar to magneplanars (they weren't magneplanars but a cheaper generic clone which I forget the name of)
I asked my friend "Wha Hoppen to the Electrostats???" (which he had worked very hard on beating them into submission and was very proud of them , and they did sound good until they suddenly hit the stops.)
"I saw Eliot poking around back there" (Eliot was their toddler)
You probably don't want electrostats around small chilluns or certain pets. jmo
Direct-driven/transformer-less ESL's can be especially dangerous because the potential lethal drive current is carried through exposed speaker cables, likely not designed for that much voltage, and that makes it dangerous even if the remainder of the speaker is safely built. Transformer driven ESL's can be dangerous too, if the stators or step-up transformers are exposed. Most DIY ESLs use poorly insulated perf metal stators, inadequate wiring, and would not pass UL testing and approval, as commercial speakers must.

That said; it isn't difficult to build a safe ESL-- it just takes a bit more effort and expense. My own ESLs use insulated wire stators which I can touch without danger while they are playing, and front & rear grill covers offer an added level of protection. The speaker cables don't carry lethal current, drive cables are insulation-rated for 30kV, and the electronics package is totally enclosed in an impact resistant, high dielectric strength polycarbonate cover. Even so; if I had toddlers or pets, I would secure the magnetic grills with straps so that they could not be removed. That's what it takes to build a safe and reliable ESL.

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Interface .jpg
 

MattHooper

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I've always been intrigued to hear the Janszen Audio electrostatic speakers. They are a hybrid design with woofers as well, but the intriguing thing
to me is it's a sealed box design, so the stat panels are not used in a dipole mode:

https://janszenaudio.com/

I've wondered if perhaps this design might somewhat avoid what to me is the more weightless sound of dipole stats.
Anyone heard them?
 
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I have had a pair of Janszen Valenina P8's for over a year, like them a lot, and have no desire to change. I feel that the information about them on the Janszen Audio web page accurately describes this speaker. What I cannot verify by measurement, my observations have given me no reason to doubt. If I say any more than this on this forum, and argument will ensue, and I just don't want to get involved.
 
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I've not heard the new Janzen speakers, only a few reviews, which were all positive. I'm curious though, about the following statement on Janzen's website:

"If you're a woman, you may be glad to know that the critical range of frequencies, where conventional speakers tend to sound harsh, is instead as smooth as silk. This is because that range (1 kHz – 3kHz) is on the electrostatics, which are incapable of making peaky sound."

Do women really perceive sound differently than men?

My own ESL's are quite capable of making peaky sound in the 1kHz - 3kHz range, so if the Janzen's can't, I can only assume it's because their stat panels are significantly smaller than those in other hybrid ESL's. Of course, monopole panels can be smaller because they don't suffer the dipole roll off. Also; most other hybrids use larger and taller panels, which tend to have a rising/ peaky frequency response due to beaming of the highs, combined with the lows being pulled down by the dipole rolloff. Significant EQ'ing is required to flatten the response curve of a tall/thin dipole panel.

Some have described the ESL sound as "weightless". I'm not sure what that means. If we correlate weight to sound pressure, then it should be measurable and quantifiable. I will venture a conjecture that the "weightless" perception may correlate to what I call "mid-bass suck out"-- that is; the dipole cancellation pulling down the mid-bass.

In a conventional hybrid ESL, the onset of dipole roll off, and severity of the resulting "suck out", are determined by the panel's baffle width and the crossover frequency. The suck out can be mitigated by widening the baffle or raising the crossover frequency or [to a limited degree] applying judicious EQ'ing. Generally; the speaker design will implement all three options.

My perceptions are pretty much limited to experimenting with my own hybrid ESLs, which have panels that are larger than most, and highly efficient. If I set the crossover frequency too low (<200Hz) the mid-bass lacks punch and no amount of EQ'ing will compensate it (beyond near-field). Conversely; raising the crossover frequency restores the mid-bass punch, with less EQ boost, which means I can drive the panel much harder (to painful volume, actually) before driving the diaphragm into a stator.

When properly configured and tuned; I do not perceive my ESL's being "weightless" all all.

In my experience; I can only relate the "weightless" perception to lacking punch in the low-mid octaves.

Back to the Janzen's:
The stats are quite small in this speaker, so I figure the crossover frequency would need to be north of 400Hz. If the balance is correct; then perhaps this ESL would not be perceived as "weightless".

As with the author of the previous post; I too would not want to get involved in any arguments. Just offering some food for thought...
 
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LarsS

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This T&A speaker has been on my shortlist for many years.

”The electrostatic unit is of identical construction to that of the CWT 2000, and its circuitry is similar. For this reason it is equally effective at transmitting the entire high-frequency range from just under 2000 Hz to more than 40 kHz – even well off-axis!
The 12 cm mid-range unit is of similar design to the 15 cm mid-range driver, and offers the same superb ability to handle the full vocal range from 200 to 2000 Hz. Once again this unit’s outstanding attributes are its dynamic ability, its inherently lively nature, and its unbelievably natural sound. With this size of cone a phase plug is not sensible, and unnecessary in any case.
The damping of the speaker cone is very effective, eliminating any hint of resonance, and the cone features integral stiffening channels. The large magnet and the carefully calculated suspension system ensure perfect transient response characteristics in the separate mid-range chamber. Since the loudspeaker is fitted with an array of no fewer than eight of these units, the cone excursion is very small even at extreme levels, and this eradicates potential intermodulation effects in the mid-range.
A sealed bass enclosure houses four large, perfectly matched 22 cm bass units, with big magnets, extremely stiff cones, ultra-long linear excursion and very low resonant frequency; these drive units are responsible for the speaker’s surprisingly deep, powerful bass, which is incredibly dry and precise.”
https://www.ta-hifi.de/en/loudspeak...ing_wp_cron=1619186536.2957689762115478515625


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I've always been intrigued to hear the Janszen Audio electrostatic speakers. They are a hybrid design with woofers as well, but the intriguing thing
to me is it's a sealed box design, so the stat panels are not used in a dipole mode:

https://janszenaudio.com/

I've wondered if perhaps this design might somewhat avoid what to me is the more weightless sound of dipole stats.
Anyone heard them?
I own a pair of Valentina Active.
When I was shopping for speakers, I was "sold" to the principles (or marketing?) of ESL. I listen mainly to classical music, and definitely (subjectively) heard the very clean clear ("fast"?) strings and pianos sound on ESL.
I really wanted to buy a ML (the ESL-11). To my own surprise, I heard a harshness in the mid and upper treble (sorry, no scientific measurements here to back up). I went to differing dealers with different setup over the months, but that same problem remained. I also tried the ESL-9 without success.
Then I heard the Janszens: ESL in a closed box. The clear "fast" sound of the strings remains, no harshness and no over-brightness. They can very well be positioned close to walls, unlike the open dipole. They do not have that "spatial" diffuse sound of the open dipole, but more of a focus "binaural" quality. And they are very directive horizontally and vertically. Again, I wish I have all the measurements to concur.
I just received my UMIK-1 and installed REW. Learning to do measurements and DSP. Maybe I will have something more scientific to share next time.

Another ESL speaker that I would love to dig further: Muraudio SP1: https://www.muraudio.com/sp1
Heard them in an audio show, they sounded very promising. However, the price slowly crept up from US$12k initially at launch, to almost US$17k now, out of my range.
 

steve f

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http://www.phaselinearhistory.stereomanuals.com/andromeda.htm
View attachment 105203
View attachment 105204

Anyone ever hear these dipoles from Bob Carver? I have. They had something like the early Carver Holographic cross talk cancellation built into them. They actually sounded pretty good. The Holographic thing worked quite well if you had a big room to stay well away from the boundaries. And it was the most head in a vice speaker ever if that Holographic system was going to work. Widest imaging you'll ever hear I think.

Those funny looking drivers up top are like if you took a regular 4 inch midrange driver. Pointed it at the ceiling and mounted it in a baffle so half the cone is on the front and half on the back. Bizarre, but it worked.
I saw a pair at a dealer many years ago. They couldn’t get them to work.
 

Eurasian

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Forgive me if I go a bit overboard but I love talking about this stuff.

Discussions of ESL’s versus dynamic speakers usually touch on their respective narrow versus wide dispersion patterns. Some love the beaming (magical imaging) and others hate it (head-in-a-vice effect). Unfortunately; physics doesn’t permit having both the magical imaging and a nice wide sweet spot, simultaneously.

Personally; I love being in the focus of a big pair of flat panel ESLs… but not for long periods, and not at all when guests drop by (as not everyone can sit in my lap).

Both the curved ML’s and the sequentially phased Quads remedy the head-in-a-vice effect; although I prefer the Quads.

A lesser known but more versatile remedy for the head-in-a-vice effect employs electrically segmented stators. Some commercial versions have a separate narrow stator section for treble frequencies, and some have three stator sections for the lows, mids, and highs.

Some cutting-edge ESL’s in the DIY community use symmetrical, multi-segment wire stators to tailor the dispersion. This scheme is somewhat analogous to the Quad model 63, with some important differences explained below.

The Quad 63 uses a separate mid/high center panel, with concentric ring conductors powered sequentially thru an LC (inductor/capacitor) delay line, to emulate a point source projecting a spherical wave front.

Below is a schematic of a multi-segment wire stator ESL employing (15) six-wire groups driving the diaphragm from the center-line outward-- to emulate a line source projecting a cylindrical wave front.

In any driver circuit, inserting a series resistor, with a capacitor in parallel, forms a first-order low-pass filter. In the case of a segmented ESL; the separate wire groups, coupled with the opposing oppositely charged diaphragm, are the parallel capacitors. We need only insert the appropriate value series resistors between these wire groups to form a series of low-pass filters—as shown in the schematic below.

As driven by the segmented stators; the entire diaphragm radiates the lower frequencies, but the filter network limits the highest frequencies to only a narrow vertical band in the panel centerline. And the filter network progressively chops off the highs, moving toward the panel edges.

In addition to the frequency attenuation; the charging time of the wire group capacitors also imparts a progressive phase change which slightly curves the wave front. The effect is wide, smooth trending dispersion, as visually depicted in the directivity sonograms shown below. The sonograms compare a non-segmented flat panel, a curved panel, and a segmented panel.

View attachment 125669

View attachment 125671
Would you please pm me with details on the ESLs you have for sale? Thanks, David
 
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I do have both Microscript electrostatic headphones (with new membranes) and Sennheiser HD 560 headphones from the 70s.
It is ca 1 am right now and I am sure if I would start listening (on my Microscript) to one of Lou Reed's binaural recordings right now that I won't go to bed before 3 am. The Microscript electrostatic sound is simply addictive. This is not the case with the Sennheiser but I don't know why....
PS a bit off topic, sorry.
 

Wes

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Best thing about electrostatic speakers is that you can use them as bug zappers
 

JustJones

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I haven't heard ESLs in years but I've wondered about the JanZen this is what they show on their site.

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    • 30 Hz - 20 kHz in medium to large rooms
    • 20 Hz - 20 kHz in small rooms
  • Maximum continuous SPL from pair at sweet spot
    • 112 dB in small room at 8’ distance [2.5m]
    • 108 dB in medium to large room at 13' [4m]
    • Peak transient SPL at least 6 dB higher
  • Dispersion pattern: Unipolar: enclosed cabinet eliminates backwave, easy setup compared to other electrostatics
  • Listening area
    • 20° horizontal dispersion at 15 kHz
      • 6.5’ wide at 13’ [2m wide at 4m]
      • 4’ wide at 8’ [1.2m wide at 2.5m]
    • Controlled dispersion -- uniform frequency response over a known angle; rolls off rapidly beyond
      • conserves recorded ambience
      • sharpens the soundstage
      • reduces interaction with the room, especially reducing wall splash
      • involves the room enough, however, to avoid in-your-head imaging
 
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I do have both Microscript electrostatic headphones (with new membranes) and Sennheiser HD 560 headphones from the 70s.
It is ca 1 am right now and I am sure if I would start listening (on my Microscript) to one of Lou Reed's binaural recordings right now that I won't go to bed before 3 am. The Microscript electrostatic sound is simply addictive. This is not the case with the Sennheiser but I don't know why....
PS a bit off topic, sorry.
I did the test with the Lou Reed albums "Take no prisoners" and "Animal serenade" and the magic was there instantly. Lou Reed is so funny and sharp on the live binaural album "Take no prisoners" so I did not go to bed until 3 AM!
 
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