ESL's and humidity?

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My old ESL panels are very prone to losing sensitivity when the humidity is high. I'm about to put together a new design and want to avoid the old problem. What design features are necessary to make an ESL humidity independent? I am planning to use the ER Audio coating for my new panels; I used graphite powder for the old ones. Also, in the old panels I made electrical contact to the diaphragm at only one point on each panel. I plan to use run copper tape all the way around the perimeter of the new diaphragms. Am I on the right track?
 
I don't recall seeing guard ring techniques used to prevent diaphragm leakage in humid weather, but if there were a safe way to do it, it seems like a promising approach. This assumes that the coating is limited to a specific area (like the painted-on stuff that I use). Moot point for me here in California...
 
If your panel looses sensitivity at high humidity, than the cause is not in the coating. Even the worst HC systems will conduct even better at high humidity.
It is probably caused by dirt (which conducts better at high humidity) and/or discharge at badly insulated parts.
Hopefully cleaning the esl will help.
 
There's little doubt that my current ESL panels have accumulated dust and dirt that is at least exacerbating the charge loss from the diaphragm. Since I'm building new speakers anyway I've chosen not to bother trying to tear apart the old ones to fix them. I just want to be sure the new ones don't suffer from the old problems. It's reassuring that what I've been planning for the new panels has worked for others. Onward with the construction! Thanks for the responses. If anyone else has hints or thoughts to offer, by all means pass them along.

Few
 
It is a known fact that in Singapore and places of similar humidity that unless you have an air conditioned room it is a waste of time owning ESL's, even here in Australia in our summer in Sydney I have monitored the HT on many ESL's and all loose HT charge on humid days even brand new pannels will loose it.
The humidity sucks the charge straight off the mylar, and if the pannel is dirty it can ALSO form conductive tracks when the dirt is dampened by the humidity.
On my pristene clean Martin Logans Monoliths I have measured with an ESL HT Meter a good charge on the pannels of 5KV on days under 65%-70% humidity, but on days when it's 70% - 80% or more humidity the charge goes down on both channels equaly to 4KV and more if more humid, I don't even bother turning them on.
You loose effiecency so you have to drive the volume up harder to reach the same level. In my case it's worse as the Monoliths have a passive bass below 100hz, and on humid days it becomes more dominant as the ESL panel looses HT charge the bass doesn't, so the system becomes bass heavy.
The only one that I measured that takes a while to loose it's charge was the old Quad ESL 57, as it has a sealed dust cover over the itself and it takes a couple of days high humidity for the humidity to get ito the sealed chamber then it looses charge, but then also it takes a while for it to return to normal as well, so it's no better just different.

Cheers George
 
Well that's not very encouraging news George! Thanks for the input, though. I guess I could install dust covers and build in some way to connect a canister of desiccant to the air trapped between the dust covers, but that sure sounds like a pain. My environment isn't anything like Singapore (I'm in Maine, USA) but we do get humid days during the summer and the current speakers really lose it.
Few
 
MJ Dijkstra said:
There are very humid days here also. No problems at all with my esls.

You wouldn't know unless you have a 5kv esl volt meter, you think you or your system is just having one of those off days.

Get hold of a ESL meter then you will believe, (they're rare because they were built in the 50's but come up on ebay every now and again, the best on I've found is the Sensitive Research 5kv, a new one costs a fortune)

http://www.elecins.com/!EISPROD.HTM

Cheers George
 
Few said:
Well that's not very encouraging news George! Thanks for the input, though. I guess I could install dust covers and build in some way to connect a canister of desiccant to the air trapped between the dust covers, but that sure sounds like a pain. My environment isn't anything like Singapore (I'm in Maine, USA) but we do get humid days during the summer and the current speakers really lose it.
Few

At 80% humidity who in their right mind would want to sweat it out listening to music anyway with out aircon, fullrange stats are fine just turn up the volume a tad more, it's the hybrids like my Monoliths that have the real problem with the subjective increase in bass at 80% humidity, I just lower the gain on my bass amp and all is fixed, but the poor guys that are single amped with hybrids are stuffed, they just have to listen to a darker sounding system on humid days because of the subjective increase in bass when they've turned up the volume to compensate for the humidity.

Cheers George
 
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