Roger Sanders' views on audio: The discussion thread

[MattHooper]

Arrived late to this thread but I can give the (subjective) opinion of someone who has owned a full Sanders System: 2 x magtech amps, sanders preamp and 10c hybrid electrostat

I loved them. But I sold them.
Why? Well, in the sweet-spot they are astoundingly good. Pin point imaging, coherent (the digital crossover time-aligns the panels and the transmission-line bass units. It sounds like a single speaker ... every other hybrid electrostat I’ve heard sounds to me like there are two different speakers in the room).
And well balanced tonally. And able to go stupidly loud with dynamics equal to or better than many “box speakers”.

In short, one of the best systems I’ve heard. Period.

One problem. Music is a shared thing for me. I love listening with my family, sharing tunes with my kids. Listening with friends.
So my main system is in my living room - a shared space.
And out of the sweet-spot, the magic isn’t there.

For me beamy speakers are off-putting even if I'm using them alone. There is a shifty quality to the illusion that makes me ultra-concious of the mechanics of the illusion, and feels less natural. It reminds me of those hologram displays of objects. They are really neat insofar as they are producing a 3 dimensional image of an object, but they are very angle dependant and the image has a "shifty, fleeting" quality vs a real object.

I had a similar reaction to LCD and rear projection TVs, whose screen technology produced beamy images requiring a sweet-spot. I preferred plasma back in the day because it felt more natural. Put an image of a painting on a plasma and it had a stability like the real thing you weren't made conscious of the illusion if you moved off axis. Whereas LCD and RPTVs visibly altered their brightness and contrast if you moved off direct axis.

I like to be able to slouch around or have some level of movement where at least the tonal quality doesn't alter obviously, end even better, if the imaging doesn't shift really obviously.

I used various Martin Logan speakers for over 10 years before switching back to direct radiator speakers.

They were amazing from the midrange up.

But I could never get bombastic classical warhorses like Dvoarak's 9th to have the somatic impact in the upper bass / lower midrange 'power zone' that I liked.

I think there is something different in how they pressurize rooms.

Martin Logan always preached that they were addressing the super tight sweet spot issue by curving their panels. I never found it did much good in practice. They beam like mad like most electrostatics (my buddy has some ML hybrids and I've heard many ML speakers).

I also agree about the difference in pressurizing the room. Like I've mentioned before, when I hear most electrostatic/dynamic woofer hybrids that's one thing I notice - the range covered by the dynamic woofer has some punch and solidity, but as the panel takes over the sound becomes more ghostly - clear and boxless, but doesn't seem to move air in the room the same way. That's why I moved on from Stats to dynamic speakers

 

[thewas]

I also agree about the difference in pressurizing the room. Like I've mentioned before, when I hear most electrostatic/dynamic woofer hybrids that's one thing I notice - the range covered by the dynamic woofer has some punch and solidity, but as the panel takes over the sound becomes more ghostly - clear and boxless, but doesn't seem to move air in the room the same way. That's why I moved on from Stats to dynamic speakers

Yes, we shouldn't forget that most electro- or magnetostats are implemented as dipoles so there is a significant directivity and room loading discontinuity when they are coupled to usual monopole woofers.

 

[Wes]

Do we need a "What's the best panel speaker" thread?

 

[DonH56]

Do we need a "What's the best panel speaker" thread?

No. There are other fora for that.

 

[Jazzman53]

Is it possible to get both pinpoint imaging AND a wide sweet spot from the same speaker? Actually; no, but almost… I once built a hybrid ESL with switch-selectable wide and narrow dispersion modes. This is rather easy to do with multi-segmented wire stators.

It works sort of like a Quad ESL-63, except where the Quad used concentric ring conductors sequentially driven to function as a point source projecting a spherical wave front, a symmetrically segmented ESL uses discrete vertical wire groups driven in stepped-frequency/stepped-phase, from the panel centerline outward, to function as a line source projecting a cylindrical wave front.

A segmented wire ESL can be made to operate in wide or narrow modes by merely inserting a switch to defeat the segmentation resistor network. Switch OFF leaves the network engaged and the panel operates in wide mode. Switch ON jumps over/defeats the network (all wire groups then see same bandwidth at same instant in time) and the panel operates in narrow mode.

Below is a link to the write-up and build photos of the switch-mode ESL, if anyone is interested:
http://jazzman-esl-page.blogspot.com/2008/03/a-segmented-wire-stator-esl-with.html?m=1

The switch mode feature was fun for a while, but the novelty wore off pretty quickly because switching modes required powering off to prevent destroying the switch (a 300-volt Soviet military 8-pole rotary switch in a multi-thousand-volt circuit), and changing modes also changed the frequency response, which required re-EQ’ing the panel each time. I had memory presets for the EQ’s but it was still a pain.

I soon found myself just leaving those speakers in wide mode, even when listening alone at the focus. So; in my latest speakers (shown in the link below), I omitted the switch-mode feature and I don’t really miss it.

https://www.audiosciencereview.com/...the-discussion-thread.2615/page-7#post-419828

 

[Bjorn]

Is it possible to get both pinpoint imaging AND a wide sweet spot from the same speaker

That's very possible and also easy to achieve.

You need:
1. Speaker with sufficient broad dispersion for your "sweetspot" and the directivity should be uniform over a broad frequency area.
2. Acoustic treatment of high gain specular reflections. Especially of those that arrive early after the direct signal.

 

[Jazzman53]

That's very possible and also easy to achieve.

You need:
1. Speaker with sufficient broad dispersion for your "sweetspot" and the directivity should be uniform over a broad frequency area.
2. Acoustic treatment of high gain specular reflections. Especially of those that arrive early after the direct signal.

What you’ve suggested is exactly what I’ve done with my latest speakers and listening room, and I have to admit; it works pretty well—although I can’t say the imaging is as precise as from the narrow mode flat panel – maybe a bit more work on the room…. (??)

I think Sanders' speaker is the only unsegmented flat panel sold commercially. Except for the DIY community where they are popular; most people have never heard a flat panel ESL, and have no reference for its imaging.

Below is an excerpt from a post by my online collaborator/friend and ESL guru, Steve Bolser-- comparing conventional flat panels to curved panels and segmented flat panels:

 

[Bjorn]

What you’ve suggested is exactly what I’ve done with my latest speakers and listening room, and I have to admit; it works pretty well—although I can’t say the imaging is as precise as from the narrow mode flat panel – maybe a bit more work on the room…. (??)

I think Sanders' speaker is the only unsegmented flat panel sold commercially. Except for the DIY community where they are popular; most people have never heard a flat panel ESL, and have a reference for its imaging.

Below is an excerpt from a post by my online collaborator/friend and ESL guru, Steve Bolser-- comparing conventional flat panels to curved panels and segmented flat panels:

View attachment 67125

Yes, it's possible that you need improved treatment. It's important that early arriving reflections are attenuated to minimum -25dB and the treatment need to be effective down to the Schroeder frequency.

I've treated a room with Sanders speakers.

They do beam quite a bit, thus I wouldn't describe them as having constant directivity.

 

[Duke]

Do curved 'statics, like Martin Logan's offerings, work well in eliminating the 'head in a vice' requirement of flat panel designs? Do other problems arise using that approach?

The curve of the Martin Logans doesn't cover a very big arc, maybe 30 degrees, I used to know but don't remember the exact figure. But ime it really isn't wide enough to give a wide sweet spot.

And there is another issue, a mechanical one. You can think of that continuous curve as being a section of an expanding cylinder: When it moves forward, it gets tensioned. When it moves back, the tension is relaxed. The stress on the diaphragm from the tensioning calls for a stronger diaphragm material than what is needed for a flat-panel electrostat, and unfortunately stronger means thicker and heavier.

The SoundLab electrostats (dealer disclaimer) use a faceted-curved diaphgram so they avoid the tensioning issue, and in the initial R&D phase Roger West tested curves up to 180 degrees, if I recall correctly. He found that 90 degrees was optimum. This gives an unusually wide sweet spot, especially since the sound pressure level difference for off-centerline listeners is minor, as SPL falls off by only 3 dB with each doubling of distance from a line source.

The angle between flat facets is shallow enough that there is no "picket fence" effect as you move side-to-side.

Today 45 degrees is the standard for SoundLab. This increases the efficiency via greater energy concentration (higher SPL within the coverage angle), much like adjusting a garden hose nozzle for a narrow vs wide pattern increases the pressure within the coverage pattern. But they still offer the original 90 degree pattern as an option.

The original 90-degree pattern SoundLabs have the most uniform radiation pattern of any speaker that I am aware of. The pattern is 90 degrees horizontal (and approximates a line source in the vertical) front-and-back over the portion of the spectrum where the panel dimensions dominate, transitioning to the familiar dipole figure-8 at low frequencies. The spectrally correct power response of the SoundLabs is easily audible if you walk out of the room and listen through the open doorway, with no line-of-sight to the speakers. The tonal balance remains virtually unchanged unless the room is overdamped.

 

[Wes]

... pressurizing the room. ..

what exactly do you mean?

pressure is a well defined quantity, but you must mean something else

 

[richard12511]

I've heard the Sanders speakers (paired with the Sanders amplifiers) with and without BACCH. Without BACCH, they sounded tonally thin to me, with a tiny sweet spot; I didn't like them at all.

The Sanders speakers with BACCH are the best system I have ever heard, bar none.

How is BACCH different from something like Dirac Live?

 

[TimF]

Another Colorado specialty outfit with is own version of pure and proper. Like Target being an expression of Minnesota orderliness, and Walmart expressing Arkansas grab-bag style. Target does in fact reflect Minnesota orderliness (what we know as anal personality).

 

[Sal1950]

I posted this in another thread, but I think it deserves to be read more widely. I recently stumbled across this long interview with Roger Sanders, an independent manufacturer of electrostatic speakers.

Is he the fried chicken guy with a shave and haircut?

 

[ferrellms]

I had Acoustats for a while. They were very open and detailed, and sounded "big", but colored in ways I could never figure out, and quite beamy. Electrostatics had their day when nearly all box speakers were "boxy". The lack of physical resonances in the electrostatics made for ear-opening transparency. Of course, boxes are a lot less boxy now! BW Matrix, with cabinets that were designed to be resonance-free, were the first boxes that sounded "electrostatic" to me.

 

[Head_Unit]

edit: https://www.biline.ca/audio_critic/mags/The_Audio_Critic_25_r.pdf
Starts on page 10 (pdf 11)

oh goodness though, don't stop there, the white hat/black hat part is hilarious!