Custom ESL X Center?

[TiBoneFramer]

Call me Crazy...

I was thinking of buying a single ESLX. Flipping the panel horizontal with a gentle bend for seating dispersion. Then using the 2 8" woofers in a custom cabinet below the panel with the crossover in the box. Has anyone seen or done something like this before??

 

[JonFo]

Not sure you can bend an already bent (in the opposite orientation) panel.

A couple here have tried panels laid on their sides, but that limits horizontal dispersion to the width (original length), so at most 4' of coverage.

In general, better off with something like the C18 Focus. Since it is a monopole, it also addresses the downsides of a dipole center.

 

[TiBoneFramer]

Not sure you can bend an already bent (in the opposite orientation) panel.

A couple here have tried panels laid on their sides, but that limits horizontal dispersion to the width (original length), so at most 4' of coverage.

In general, better off with something like the C18 Focus. Since it is a monopole, it also addresses the downsides of a dipole center.

Far as I know the panel will go back to dead flat the moment it is out of the airframe.

Still better than C34 or 18.

Also I have an Illusion but want a step up and fully electrostatic panel from 3-5 hundred hz up

 

[Fidji99]

Why aiming so low? Buy 2 CLX's and flip them horizontally and place next to each other. Add 12 pieces of BF 212 and you are almost there ....

 

[TiBoneFramer]

Why aiming so low? Buy 2 CLX's and flip them horizontally and place next to each other. Add 12 pieces of BF 212 and you are almost there ....

I will but let me start with this first

 

[Fidji99]

Seriously - talk to ML directly, they might be willing to build some bespoke speaker for you. They are best positioned to build custom frame and put e.g Neolith panel in it.

 

[JonFo]

Another option is to talk to the folks at Muraudio, as I've always thought their ESL panel would do well in a center channel, as it radiates more like a point source with a very wide dispersion angle. I'd ask if they would apply the rear wave dampening from the PX to the P1, to turn it into a monopole. I'd then mount that behind an acoustically transparent screen.

In a center, horizontal and vertical dispersion is important in a multi-seat room, and the Muraudio P1 seems to have that.

 

[JonFo]

Far as I know the panel will go back to dead flat the moment it is out of the airframe

Nope, not at all. The stators start life as flat perforated metal, then powder coated, rolled into their curved shape, and then go to ESL assembly, where they are put on curved jigs. They are stacked outside of any frame, and panels of all sizes remain with the curve done at the initial step.

When we went to the MartinLogan Kansas factory back in 2007, all this was explained and demonstrated to us members of the MLOC. There was a thread with pics, but the link to the site hosting the pics is dead. But here is one showing an unmounted Summit panel being prepared to be put into the AirFrame:

 

[Robert D]

Another option is to talk to the folks at Muraudio, as I've always thought their ESL panel would do well in a center channel, as it radiates more like a point source with a very wide dispersion angle. I'd ask if they would apply the rear wave dampening from the PX to the P1, to turn it into a monopole. I'd then mount that behind an acoustically transparent screen.

In a center, horizontal and vertical dispersion is important in a multi-seat room, and the Muraudio P1 seems to have that.

Why do you think Martin Logan's top center channel speaker, the illusion, has no back behind the panel and isn't a monopole? Their other center channels like the Focus are monopole in design. It makes no sense to me.
I was reminded by you in past posts about comb filtering and how the panels being left to reflect out the back can lead to that. I know that with my old Theater i center channel, my family was having problems understanding some dialogue in movies and TV. With the Focus i got, that problem is just about completely gone. It's so much more clear. The theater i was open in the back, the focus closed. I can't assume that all of the improvement in the sound is due to being monopole, but it seems unlikely to me that is doesn't help at all.
Why doesn't Martin Logan have a closed back design on the illusion too?

 

[Nuri58]

Partly they do as the lower half of the illusion is closed back - and that puzzles me, like the EM is also partly closed at the lower part. But if your idea was truly the way to go I'd think ML would possible already have such an option abailable. The must have build quire some prototypes over time.

 

[Robert D]

Partly they do as the lower half of the illusion is closed back - and that puzzles me, like the EM is also partly closed at the lower part. But if your idea was truly the way to go I'd think ML would possible already have such an option abailable. The must have build quire some prototypes over time.

Is that lower part also a panel, or is it just the grill to protect the woofers? I think that's only a grill.

 

[Nuri58]

You're possible right. There is a cross bar so yes.

 

[JonFo]

Why do you think Martin Logan's top center channel speaker, the illusion, has no back behind the panel and isn't a monopole? Their other center channels like the Focus are monopole in design. It makes no sense to me.

It is the buyers that are the cause; too many believe that ESL must be open-back to sound 'open'.

Scientifically, this makes no sense, as it opens it up to smearing from reflected energy, causing the loss of dialog intelligibility vs a monopole design, as you have noted. This is why, to me, a C18 Focus is ML's best center. Need more output? Stack three of them.

But an Illusion could be converted to a monopole by designing and building a back-box for the ESL portion. Maybe ML will build one and offer it as an extra-cost option.

My SL3XC is a monopole these days, I use a crude back-box for now.
I've been iterating on back-box designs for it and my Monoliths for years. And when I retire, I'll actually build them.

 

[Nuri58]

The sound surely changes. I have the Stax 007mk2 headset and moving the hands around the back changes the sound tremendously - somewhat canned, but not bad. I guess if you (manufacture) work on it it could end sounding quite differently. But it sounds still analytical - open sound no hands behind the earspeaker and closed with hands on them. In any case the focus is much easier to keep dust free than was the cinema. And it sounds still open so surely a matter of tuning things

 

[JonFo]

The sound surely changes. I have the Stax 007mk2 headset and moving the hands around the back changes the sound tremendously - somewhat canned, but not bad.

In the case of cans, your experiment actually proves that adding reflections with your hands reflecting the rear wave of the transducer makes a change, and not always a favorable one.
One of the reasons open-back cans are liked is because they have no reflections from the enclosure. A well-designed closed-back will mitigate those reflections, which is why there are a good number of well-regarded closed-back cans. The AirPod Max is an awesome closed-back ANR can.

 

[Nuri58]

Exactly what I was trying to say . And the Focus surely was tweaked that way whilst the illusion another way. But maybe the reason for the open back is you might achive a better result than with a closed design. Possible requires the golden ears.

 

[Robert D]

It is the buyers that are the cause; too many believe that ESL must be open-back to sound 'open'.

Scientifically, this makes no sense, as it opens it up to smearing from reflected energy, causing the loss of dialog intelligibility vs a monopole design, as you have noted. This is why, to me, a C18 Focus is ML's best center. Need more output? Stack three of them.

But an Illusion could be converted to a monopole by designing and building a back-box for the ESL portion. Maybe ML will build one and offer it as an extra-cost option.

My SL3XC is a monopole these days, I use a crude back-box for now.
I've been iterating on back-box designs for it and my Monoliths for years. And when I retire, I'll actually build them.

I agree, hopefully ML will offer an Illusion with closed back, like the Focus. You're probably right about customer demand. I'd want a closed back on mine if I were buying one.
I also wonder why Martin Logan doesn't have a closed back on their main left and right speakers. A closed back 15a. I guess for music, maybe having those rear reflections are somehow good? The fact remains though that owners install sound absorbing panels on the wall behind to do away with reflections. Why not just have a closed back?

 

[Russr]

I'm wondering if there have been any scientific papers written on what happens with ML ELS (Dipole) speakers operating in an anechoic chamber? My gut (important audiophile device that, the gut!) tells me it would sound accurate but somehow thin.

I think that the nature of (open) ESLs contribute to some of the "magic" that folks feel/hear, but might not be entirely measurable. Don't get me wrong, I know you can measure/chart waveforms rebounding off of surfaces, etc., but crazy little changes that make close-to-zero difference in quantifiable obersaervations... things our brains interpret as "richness", "depth", "warmth", etc., etc., etc. Tiny reflections in certain places, absorptions in others, creating a sphere of sound that would be different and lacking without them.

And no, I have not been taking any pharmaceuticals recently... tho' I AM feeling a few pangs of hunger....

 

[Robert D]

I'm pretty sure there are high end elctrostats that have a closed back? Can't recall names.

 

[Nuri58]

Many headphones have open backs - also conventionel. You also have bass reflect and open port LS. Guess it's again what you want to achive. ML also went for the port on the LS but the dynamo subs are closed. Balanced force again a different approach. But the open diaphragm are at least 100% symmetrical but then again the curvelinear approach must mean that the tention is different the one way than the other meaning a difference. But in conclusion they sound good and have the WAF not achievable with a box on the back