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Electrostatic speakers?

anmpr1

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And you would be unlikely to have heard of Oakeshott even if you had done formal study of philosophy.
This is probably the case, as his contribution was mostly confined to liberal political and social theory from the 17th C, on. So in that respect his work is a subset within a subset. However, that is not an acceptable criticism of him, per se. It is more a statement of fashion. When one looks over the courses of philosophy departments today, there is not as much emphasis on his sort of thing.

When I was in grad school, within the discipline his name was known and his works both read and cited. But that was the late '70s. There are many important teachers suffering similar fate--serious scholars like Etienne Gilson et al, who are mostly forgotten because they never wrote about what is currently trendy within modern academic fashion.
 

Bob Klass

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The best speakers I ever owned were Acoustat 3's. They had three large panels in each speaker. These speakers would not play loud regardless of how you drove them. I used a 240 watt tube amp on each channel. Most other amps totally failed to drive them.

The Acoustats were ultra clean down to around 28 cycles without the use of anything but the ESL drivers. The sweet spot was tiny - stand right there. Don't move. But I loved to stick my head right up against them. Like earphones for a giant. You could hear the distortion from the amps, but not from the speakers. Unfortunately, I fried one of the transformers in one of them (trying it with a piece of crap megawatt DJ amp) and it is impossible to find or replace.

Then I bought some Martin Logan SL3's. They don't really compare to the flat, open sound of the Acoustat's but they would go louder,weren't as picky about amplification, and had a large sweetspot. The SL3's were very clean throughout the high end but not so much where it hands off to the built in conventional (ported) woofer. They are well down my list of favorite speakers (behind my Acoustat Model 3, Infinity Quantum 3, Bozak Symphony (Modern), and custom Dynaudio).
 

Hon

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I have a pair of Quad ESL, the original electrostatic loudspeaker. These are late editions from the end of their production run. To me, I have found nothing that has compared within reason.
They are indeed brilliant, aren't they? I always lusted after a pair but never met the opportunity and had to settle for lesser planars sometimes. I met a man during the time of TAA who had constructed his own full range electrostatics complete with a 3000v amp that lived in his basement, but I doubt they compared favorably with Quads.
 

Midwest Blade

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I was extremely lucky to pick up my pair of ESL's. They came in on a trade at my old audio dealer, someone was downsizing and did not have the space. I stopped on for a visit the day he first set them up, I packed then into my hatchback the next afternoon. Only thing I have had to do was repair a dust cover and give them a thorough cleaning after several years of storage.
 

misterdog

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I now have a Benchmark AHB2 powering my Quad 989's, my jaw has dropped right through the floor.
Chain is SMSL M400 DAC into Topping Pre 90 into AHB2, yes I'm a zero distortion tart.
Well that's why I bought the Quads so following the low distortion back to the source seemed an obvious step. The lower the distortion the better the dynamics and the bass, sublime.

Getting rid of the dust covers, metal protection grilles and the crap flimsy frame works wonders.
 

Bob Klass

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That's funny. My cat has no claws, but even if she did I'm not sure how she could harm my Martin Logans. Those curved electrostatic grills are nicely painted. Whatever high voltage charge is going through there doesn't seem to be anything you can feel.

My right Martin Logan sits right next to the litter box, by the way.
 

LTig

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Yep, best with something really loud playing. It works with humans. :D

When I was in my youth my father got a habit to wake me up in the morning in a way which I didn't liked at all (can't remember what it was, OMG). I begged him to stop it but to no avail. So one night I prepared my R2R deck with a recording of Richard Strauss' "Also Sprach Zarathrusta" and positioned the tape to the loudest part, hit the pause button and set the volume to max. The cable bound remote control for the R2R went under my pillow.
When my father woke me up I started the R2R with the remote control. I think he almost got a heart attack. Luckily for me he took it by the humorous side (he was a very fine man and a loving father and I miss him), but he also learned the lesson.:cool:
 
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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.

Yes,
I heard a pair of those Andromeda's at CarverFest in 2012. The subs were in terrible shape; with the woofer surrounds rotted away and only the spiders holding the cones in place... and yet they still sounded pretty darn good! I thought the conical deflectors suspended over the up-firing tweeters was a simple, effective way to disperse the highs in dipolar fashion. Pretty impressive for the time they were built. The Bobfather always did think outside the box.
 
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Hi all,
I don't know how I missed this whole thread until now-- especially since building ESL's has been my psychosis for the past thirteen years. BTW; I have two newly-built pairs for sale, if anyone is interested :)

My latest design; the Jazzman MkIII, is shown below. It's a flat panel hybrid ESL with symmetrically segmented wire stators which electronically bend the wavefront to give wider and smoother-trending dispersion than a curved panel. The details of how this is done are given on my website here: http://jazzman-esl-page.blogspot.com/

And here's a video:

IMG_2268.jpg
 
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That may well be the reason why a 'stat panel is often paired with a woofer. The trick is to get the woofer and 'stat to blend together well around the crossover region.
So true. And I think a ported or sealed box woofer arrangement will never achieve a seamless blend. I've gotten much better results using a low-induction (<0.8 mH) / low Qts (<0.5) woofer in a transmission line, and also on an OB. An OB has additional advantage of dipole radiation pattern but can't play as low because of the roll-off (a couple of subs will fix that).
 

PaulD

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So true. And I think a ported or sealed box woofer arrangement will never achieve a seamless blend. I've gotten much better results using a low-induction (<0.8 mH) / low Qts (<0.5) woofer in a transmission line, and also on an OB. An OB has additional advantage of dipole radiation pattern but can't play as low because of the roll-off (a couple of subs will fix that).
Did you miss post 54? I have a seamless blend, and I am not the only one (this is compared to a JBL M2 mastering monitor). My experience is that it is more about the distortion profile of the drive units than anything else. Look for extremely low distortion bass units to match with a low distortion ELS, and keep the xover as low as practicable.
 

misterdog

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The trick is to get the woofer and 'stat to blend together well around the crossover region.
Which is why MiniDSP developed the DSP Sub Plate Amp. Hypex also now have one.
The MiniDSP one allows for full control in real time via Ethernet, measure the room with REW and insert the filters. :)

I use 2 remote subs 1 x 12" OB and one 12" sealed box. Eminence Lab12c drivers.
 
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Did you miss post 54? I have a seamless blend, and I am not the only one (this is compared to a JBL M2 mastering monitor). My experience is that it is more about the distortion profile of the drive units than anything else. Look for extremely low distortion bass units to match with a low distortion ELS, and keep the xover as low as practicable.

Hi Paul,
I should clarify: My comments were in reference to blending a mid-bass woofer to the panel in a hybrid ESL, like a Martin Logan or the DIY speakers that I build-- not blending a subwoofer to a “full range” ESL where the crossover frequency can be much lower.

In most hybrid ESL’s the crossover point occurs in the low midrange (300Hz or higher) where our ears more easily detect subtle differences in transient response and phasing errors (made much worse if the crossover uses a passive inductor).

The commercial hybrids I’ve heard sound like two separate drivers rather than a single, coherent speaker, and hybrids specifically were the focus of my critique. To be fair; I’ve only heard lower end commercial models with passive crossovers, not higher end models with DSP crossovers.

All my speaker builds have been hybrids with digital crossovers, mated to a low-inductance woofer with Qts <0.5. The Qts thing is a double edge sword, in that too low (stiff suspension) requires more EQ’ing, and too high (floppy suspension) gives excessive overshoot and poor tracking. I think low inductance trumps all else, though, as the back EMF really impedes transient response.

I once attempted to blend a sealed box type sub to my hybrids, with poor results because it excited my room’s resonance mode (sounded like one-note bass). But then I had excellent results adding a pair of Ripol subs, as these are folded baffle dipoles, with an off-axis null which doesn't excite my room’s resonance mode.

BTW; your speakers look very nice indeed! It’s apparent you put some thought into the arrangement, and it paid off.

Jazz
(Charlie)
 
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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.

schematic.jpg


sonograms.jpg
 

gene_stl

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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
 
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