Martin Logan ESL X three strips don’t emit sound at all

[proaudit]

Hello,
I’m experiencing an issue with my 2022 Martin Logan ESL X speakers.
One of the speakers has started sounding more muffled, with weaker high frequencies. I ran the sound testing mode on the speakers and found that the lower part of the electrostatic panel in one of them isn’t emitting sound. By listening closely, I noticed that three or four of the lower strips on the panel aren’t working.
Over a day ago I powered off the speakers.
First, I vacuumed them and then moved the panel to the second speaker.
Nothing changed—three strips don’t emit sound at all. I marked them with my fingers in the photo.
Three of us listened and all confirmed that these exact three strips aren’t working.

What should I do in this situation? Thanks

 

[ttocs]

If repeated vacuuming in the affected area doesn't fix the issue, then you'll need to contact Martin Logan for Warranty Service.

From the manual:
"WARRANTY AND REGISTRATION
Your EM-ESL X speakers are provided with an automatic Limited 90 Day Warranty coverage. You have the option, at no additional charge, to receive a Limited 5 Year Warranty coverage. For your convenience MartinLogan offers online warranty registration at www.martinlogan.com."

 

[Tosh]

Assuming the HV charge is not reaching the diaphragm in that area, you could try to squeeze or massage the edges together on the side where the wires attach (on Ascent it's on the R side), attempting to make better contact. Try while it's playing. Have dry hands...

Actually, try first with them powered on but with silence playing and see if you can hear the tell-tale squeaking of HV leaking away or migrating around while pushing and squeezing the ESL sandwich together.

 

[Jazzman53]

Assuming the HV charge is not reaching the diaphragm in that area, you could try to squeeze or massage the edges together on the side where the wires attach (on Ascent it's on the R side), attempting to make better contact. Try while it's playing. Have dry hands...

Actually, try first with them powered on but with silence playing and see if you can hear the tell-tale squeaking of HV leaking away or migrating around while pushing and squeezing the ESL sandwich together.

That's an idea worth trying. Perhaps I can add to it:

It's helpful to understand how the panel is constructed. On the older ML Theater panel (the only ML panel I've seen disassembled), the diaphragm's conductive coating was not continuous but applied to each cell individually, and only in the center area of each cell. Areas within 1/4" of the spars were not coated (I think I know why but it isn't relevant to this discussion).

The Theater panel used a full-periphery charge ring to conduct the bias voltage onto the diaphragm. This charge ring remained firmly adhered to the diaphragm after the front stator was removed, although some remnants pulled away with the front stator.

In any panel constructed in this way; a broken connection could affect some cells and not others.

The fact that cells above the dead cells still play indicates that the charge ring is intact, and since a full-periphery charge ring would engergize the cells from both sides, a break on one side would not disable a cell. A fully lost connection is a longshot, but it has to be ruled in or out to diagnose the fault.

Assuming this speaker is constructed as described above, I see three possible causes:
1) The coating itself has lost conduction in the dead cells (only).

2) The stators have locally separated on both sides of the panel, and the charge ring pulled away with the opposing stator.

3) ML now bonds the charge ring onto the opposing stator, and it has locally separated on both sides.

Suggestions:
1. If any separations are found, clamp them closed as Tosh suggested. If output is not restored; bypass the charge ring as follows:

2. Find the bias supply wire and splice into it with another length of wire. Strip back 1/4" of insulation from that wire end and insert it into the panel edge at a dead cell. Do not allow the exposed wire end to contact a stator--- carefully insert the wire between the diaphragm and [upper stator] spacer tape.

If output to that cell is not restored, the diaphragm coating has lost its conduction and the panel will have to be replaced or refurbished.

Good luck with your panel!