Electrostatic speakers?

[mhardy6647]

You in Harvard? One of my favorite places in the area.

We lived there for 23 years. It is indeed a beautiful part of the world.
We retired to the New Hampshire "Upper Valley" -- a little quieter environs.

 

[617]

We lived there for 23 years. It is indeed a beautiful part of the world.
We retired to the New Hampshire "Upper Valley" -- a little quieter environs.

I'm in the city, one day I hope to join you although Harvard is plenty quiet for me.

I guess I did just buy an apple tree though.

 

[mhardy6647]

Harvard, as I am sure you know @617, is very much apple country. Dandy apples to be had.
The actual Johnny Appleseed was from nearby Leominster ("Lemminsta", as the locals would say), MA.

Actually, the apples up here aren't too shabby, either.

 

[Newman]

...The key to seamless integration was using a low-Q [i.e well damped] woofer with low-inductance [i.e. minimal back-emf for faster transient response] mounted on an open baffle to match the ESL's dipolar radiation pattern. The low-Q woofer sacrifices deep bass extension to prioritize a seamless blending with the ESL, so subs are required for the bottom end (below 60Hz)...

The very use of the term 'faster transient response' for subwoofers, and also the second idea of linking it to back-EMF, reveal false notions of what causes speakers to sound like they do.

"Fast" (or "faster") was not the best choice of words here but I do think transient response (in addition to a well damped suspension) is important for blending a woofer in a hybrid ESL.
My inference that that the mid-bass woofer's back-EMF affects it's transient response follows from the back-EMF opposing the drive signal, and since a low-inductance voice coil generates less back-EMF, it follows that lower inductance gives better transient response.
I neglected to mention the importance of the woofer having a well designed shorting ring (or rings) to minimize its inductance, as opposed to merely having fewer turns in the voice coil, giving lower drive force.
In fact, for integrating a woofer in a hybrid ESL, I prioritize its voice coil inductance over [even] its moving mass, for best transient response in the crossover band.

None of the above is true, or relevant to a discussion of what causes speakers to sound like they do, unless the amp has horrendously low damping factor.

So much of the lore surrounding electrostatic speakers is myth. A here we see yet another.

Assuming a decent standard amp, ie a typical bread-and-butter amp with high global NFB and low output impedance, all you need is a sufficient current margin of at least two, lets say three is plenty, compared to the current needed for an 8 ohm resistor, then once that is sorted, back EMF has no role, hence choosing a woofer that has less back EMF via less inductance has no role, and the whole idea that it has a link to 'blending sonically' with a stat panel has no truth.

This is why I entered this discussion: it is the old 'fast bass' discussion, and it is just not right.

The far more likely reason for one to prefer a subwoofer with diminished LF extension, like a Ripole, is because you are just not doing a normal subwoofer correctly. You know what really causes a subjective impression of slow bass? A strong, deep-reaching subwoofer without any room correction. And the answer to that....well I just wrote it in the description. But people just won't do correction and do it properly. So the next-least-worst option is to have less bass. It can't ring if it isn't there in the first place, right?

And that's the reason why a dipole woofer will seem 'faster'. It has nothing to do with inductances and back EMF.

It would make sense to repurpose the drivers from a Ripole project and put each driver into its own, normal, subwoofer box, position them around the room in accordance with multi-sub acoustical guidelines, and get interested in doing room correction properly to eliminate ringing and perceptions of slow bass. Vastly better bass all round, and should be no integration problem as long as the panels are not doing 'bad bass' above the crossover frequency.

cheers

 

[Mr. Widget]

One of the Electrostat 3s is visible (under a R/S 40-1375 leaf tweeter in a plastic Hammond cabinet) to the right of the FrankenAltec.
_____________________
* i.e., only one driven membrane -- the Quads and most if not all other good electrostatic drivers are push-pull, with both sides' membranes driven.

Sorry to drift OT.

Decades before accurate acoustic measurement equipment was available for less than many thousands of dollars all of my projects were created without the aid of acoustic measurements. Back then I used the JVC ribbon tweeters above the Audax 1.5" dome mid/tweeter to great effect. When the JVCs were no longer available and Radio Shack started selling their version I tried a pair of the RS 40-1375s. They looked identical, but they didn't sound nearly as extended. How do your Radio Shack tweeters measure?

 

[misterdog]

It would make sense to repurpose the drivers from a Ripole project and put each driver into its own, normal, subwoofer box, position them around the room in accordance with multi-sub acoustical guidelines, and get interested in doing room correction properly to eliminate ringing and perceptions of slow bass. Vastly better bass all round, and should be no integration problem as long as the panels are not doing 'bad bass' above the crossover frequency.

Which is why I use seperate amps for the subs and ESL's, both fed full range signal, the MiniDSP plate amp for the subs allows for room correction.
I believe that is the room reflections from the subs that gives the impression of 'slow' muddy bass as do the dust covers on the Quads.
Also the closer I have got to zero distortion on DACs and amps the better the bass becomes on the Stats.

I'm still wedded to the idea of my dipole sub matching the output pattern of the Stats , though I have the benefit of over a Metre of air behind it, 'potentially' mitigating rear wave cancellation. Once you get to enjoy the 'no box' benefits from Stats the idea of adding it back with Subs seems like a backward step.

 

[misterdog]

So much of the lore surrounding electrostatic speakers is myth

This is so true..

I was deterred from building solid steel frames for years after an internet 'expert' 'stated' that Peter Walker had designed the ESL 63 frame to be lossy.
The reality is that it was built this way to keep down weight and cost. Profit over ultimate performance.
In the same way that the front feet are thicker than the rears, rather than building the frames so that the centre of the panel is at ear height. Peter Walker placed his 63's on furniture to raise them.

As for the dust covers, well after several years of use after removing them I've had no issue, and once the covers loose tension they flap around.

The panels however can arc, and pierce the membrane, causing an expensive or time consuming repair, this is not an internet myth.....

 

[30 Ounce]

I have had Martin Logan CLS II since 1991 ( bought used and replaced the panels). The only subs that I found that integrated well were Entec servo and later Velodyne servo. I let the panels run full bandwidth and used the subs below 50-60 hz.

 

[Digital_Thor]

All these panel speakers I've heard, all had that directivity thing going on, because a larger area radiate the same frequencies and you therefore hardly move your head before everything changes character - IMO. They can sound nice with some classical music and choirs, but I really prefer a more narrow speaker with either waveguided tweeters that are crossed low or coax.
They also play backwards, requiring a long distance to the rear wall - often 2-3m minimum is best - IMO. And the mix of different driver types, often create issues, too. So adding a woofer to panels... well... just not optimal.

 

[misterdog]

^ It's all about opinions but did you read post 874.
If everything sounds different as you move your head, you've never heard a panel system configured correctly.
I tried some Martin Logan Electromotion ESL's because they looked so good.
Problem was the sound was abysmal.

Though I've spent 20 years getting my system to where it is now.

 

[Digital_Thor]

^ It's all about opinions but did you read post 874.
If everything sounds different as you move your head, you've never heard a panel system configured correctly.
I tried some Martin Logan Electromotion ESL's because they looked so good.
Problem was the sound was abysmal.

Though I've spent 20 years getting my system to where it is now.

eh... when you say configure - do you mean EQ? Because you do know that EQ can't change the power response, right?

 

[misterdog]

when you say configure - do you mean EQ?

No.

 

[Digital_Thor]

No.

An elaboration would help quite a bit, on how I should interpret your definition of "configuration"

 

[misterdog]

An elaboration would help quite a bit, on how I should interpret your definition of "configuration"

Perhaps set up would be a better description.

One example is that by looking at all the info, my preamp performs best at maximum output, so by using an amp with switchable gain, and setting it to low gain (again it's best measured performance) I achieve a win with gain matching.

Another is to learn to use a soldering iron so you can disassemble your speakers, IIRC there are some 150 solder joints , just connecting up the panels.
Another is to learn that just because the Martin Logan Electromotion speakers look gorgeous, doesn't mean they will sound great.
Panel speakers have to be the size of a door to work properly IMO.

Examine every small detail over 20/30 years and optimise the 'configuration' of your system.

 

[Blumlein 88]

Perhaps set up would be a better description.

One example is that by looking at all the info, my preamp performs best at maximum output, so by using an amp with switchable gain, and setting it to low gain (again it's best measured performance) I achieve a win with gain matching.

Another is to learn to use a soldering iron so you can disassemble your speakers, IIRC there are some 150 solder joints , just connecting up the panels.
Another is to learn that just because the Martin Logan Electromotion speakers look gorgeous, doesn't mean they will sound great.
Panel speakers have to be the size of a door to work properly IMO.

Examine every small detail over 20/30 years and optimise the 'configuration' of your system.

Related to this, there are some circumstances where a somewhat narrower directionality might be an advantage. For a long time I had a long, but narrow room. Speakers had to go close to the side walls. I had space behind them. I'm not sure a wider dispersion is good in that situation. It also meant the front to back cancellation was less as one side of my panels were quite close to the wall. When looking toward the speakers from the listening position, the panels were about 45% of the area of the end of the room. The sound using panels that way was very good.

 

[Digital_Thor]

Related to this, there are some circumstances where a somewhat narrower directionality might be an advantage. For a long time I had a long, but narrow room. Speakers had to go close to the side walls. I had space behind them. I'm not sure a wider dispersion is good in that situation. It also meant the front to back cancellation was less as one side of my panels were quite close to the wall. When looking toward the speakers from the listening position, the panels were about 45% of the area of the end of the room. The sound using panels that way was very good.

Did you dampen the first reflection from the side walls and EQ the bass?

 

[misterdog]

Did you dampen the first reflection from the side walls

Stats don't excite the room in the way that box speakers do, my stats are only 30cm from the side walls.
Maybe due to the fact that the membrane has maximum (around 1mm ) excursion at the centre of the panel, hence you could say that the speaker is 65cm from the side wall.

I suspect that the best improvement for my system would be a bigger room though..

 

[Blumlein 88]

Did you dampen the first reflection from the side walls and EQ the bass?

No.

 

[Digital_Thor]

No.

Fair enough. I did not do that with my speakers either. But rebuilding them with drivers and filters, that gave a way more controlled dispersion, helped a ton in this regard, when the walls are close. Things you can't do with panels - that's why I asked if you compensated with damping, at the first reflections, so that the direct sound could dominate more, hopefully leaving you with clearer sound overall.

 

[lewdish]

I have to agree that most hybrid ESLs never quite sound like a single, seamless speaker.

The only commercial hybrid ESLs I know of are from Sanders, Janzen and Martin Logan. Of those; I've only personally heard the older Martin Logan models, which in my opinion had good bass extension and punch but lacked seamless integration between the woofer and ESL panel.

The only full range ESLs I've hard are the Quad 57's and 63's. Their bass extended surprisingly low but wasn't as punchy as hybrid designs and was also a bit boomy and ill-defined at the bottom end, which I attributed to the diaphragm's drum-head resonance.

I've been an ESL designer and builder since 2008, and to-date I've built 20 pairs, in several configurations.

The challenge in full range ESL is mitigating the nasty-loud drum-head resonance. In a hybrid the stat panel doesn't have to play down low where the drum-head resonance dominates, but its challenge is achieving a seamless blend between the woofer and panel.

I wanted something different than the commercial ESLs I had heard so I took a different path; initially favoring hybrids with transmission-line bass, and now hybrids with segmented wire-stators and dipolar bass.

My latest and final hybrid ESL build sounds like a single-driver with the cleanest bass I've ever heard.

The key to seamless integration was using a low-Q [i.e well damped] woofer with low-inductance [i.e. minimal back-emf for faster transient response] mounted on an open baffle to match the ESL's dipolar radiation pattern. The low-Q woofer sacrifices deep bass extension to prioritize a seamless blending with the ESL, so subs are required for the bottom end (below 60Hz).

Building my speaker is more work than any sane person would attempt but I freely share my CAD drawings and all build info with other DIY'ers.

If interested; here's my website: http://jazzman-esl-page.blogspot.com

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?