Martin Logan "Vertical Spacers" as an upgrade

[Pars]

Dear All,

I was up for panel renewal in Germany and I came across a website who offers vertical spacers instead of horizontal ones. Well, the claim is better sound but I wonder if this is the case why does ML use it from the start? Maybe for flat panels it can be good but for curved ones I believe horizontal must be the way to go. Does anyhone has an experience with Vertical Spacer" application? Does the sound change or Frequency response effected?

And by the way, Vertical is more expensive than Horizontal... :

Thanks in advance

 

[Russr]

Got a link or any other reference material?

 

[JonFo]

FYI, the MartinLogan CLS had long vertical spars.

 

[Pars]

FYI, the MartinLogan CLS had long vertical spars.

Oh! I didn't know that.

 

[Pars]

Got a link or any other reference material?

 

[Pars]

Oh! I didn't know that, it seems like combination of two but need to check more

 

[Pars]

http://loudspeaker-repair-service.reromanus.net/magnepan.htm

 

[Leporello]

Dear All,

I was up for panel renewal in Germany and I came across a website who offers vertical spacers instead of horizontal ones. Well, the claim is better sound but I wonder if this is the case why does ML use it from the start? Maybe for flat panels it can be good but for curved ones I believe horizontal must be the way to go. Does anyhone has an experience with Vertical Spacer" application? Does the sound change or Frequency response effected?

And by the way, Vertical is more expensive than Horizontal... :

Thanks in advance

The size and shape of each section determines the drum resonance. They are staggered, which shapes the overall frequency response. There is usually a compensating network inside the electronics which further shapes the response. Also, the dimensions of each section are constrained by stability considerations, otherwise the diaphragm could stick to one stator. Martin Logan has been making these panels for a long time. You shouldn't mess with their original designs unless you know what you are doing. Maybe this company does but if its only selling point is vertical=better sound, with no further explanation, I wouldn't bet on it.

The CLS II, IIa and IIz had wide and narrow vertical sections on each side--the pair are mirror images. The original CLS apparently did not, according to the product museum. It's my understanding, and it could be wrong, that the panels for the II, IIa and IIz are the same, only the electronics are different. Only the original CLS panel is different.

 

[Leporello]

FYI, the MartinLogan CLS had long vertical spars.

Your link is to the CLSIIz, which did have verticals. The original CLs didn't.

 

[Pars]

I asked directly to ML and here is their answer:

Martin Logan uses horizontal spacers in their electrostatic speakers to optimize the performance of our curved panel design, known as the "Curvilinear Line Source" (CLS). Here's why horizontal spacers are preferred:

1. Sound Dispersion: The curved shape of the electrostatic panel allows for better horizontal dispersion of sound. Horizontal spacers maintain the integrity of this curve, ensuring even sound distribution across the listening area.
2. Mechanical Stability: Horizontal spacers provide structural stability to the large, curved panel without interfering with the vertical alignment of the diaphragm. This alignment is critical for consistent performance and minimizes distortion.
3. Electrostatic Field Consistency: The spacers help maintain a uniform distance between the diaphragm and the stators (the charged plates on either side of the diaphragm). Consistent spacing ensures a stable electrostatic field, which is crucial for accurate sound reproduction. Horizontal spacers are better suited to maintaining this consistency across the curved surface.
4. Aesthetic and Acoustic Design: Vertical spacers could interrupt the visual and acoustic continuity of the panel. Horizontal spacers are less intrusive and allow for a cleaner design, both visually and in terms of the sound wave's interaction with the room.

 

[Jazzman53]

I've used both horizontal and vertical spars in DIY ESLs, and either work fine as long as the design accommodates the choice. Even so, I would need convincing that vertical spars on a cuved panel is more advantageous than horizontal spars.

The only advantage I can envision is eliminating the asymmetric hoop constraint on the diaphragm. That is; a curved diaphragm's forward motion is more constrained than its rearward motion, because the forward motion is expanding a hoop (fighting against its own tensile strength). Whereas; there is no hoop constraint with vertical spacers because the diaphragm is then multple flat facets, with no curvature.

The span between vertical spars is necessarily small to accommodate the curved stators (else the diaphragm facets would intersect the rear stator). Moreover, the spars' short/equal spans create a very loud, single peak [diahragm] drum head resonance.

Whereas, the passive ML crossover would be tuned to work with wider-span, unequally spaced horizontal spars which break up the single loud drum head resonance into multiple softer resonance peaks spread over a wider bandwidth. And I suspect ML uses the resonance energy to mitigate the panel's low fequency dipole rolll off.

In contrast; short-span, equally spaced vertical spars would produce a much louder single-resonance peak at a higher frequency, which would not help mitigate the dipole roll off, and would not match ML's crossover tuning.

I can see how this configuration could be made to work and even sound good, provided that the system is bi-amp'd with a DSP crossover tuned to accommodate the drum head resonance (i.e. diaphram tensioned low enough to permit setting the crossover frequency a full octave below the resonance, in order to avoid exciting it).

On the other hand, a Frankenstein mix of vertical spars mated to the original passive crossover seems like audio Russian Roulette to me.