our (cadence speaker owners') experience in delhi has been quite contrary. we are a mix of old and new ES panel material, the older being the aluminum based and the newer being the indium oxide coated teflon (Fraunhofer Instt.) (incidentally, the ML ES also use the similar material from the same source). another new foil owner and i (also new foil) had a lot of challenges all through these monsoons that were exceptionally heavy leading to a lot of humidity indoors. could not enjoy music for close to two months!! :annoyed:
the panels would just crackle or o/p very low DBs.
my 'solution' was a round of sunning, (car) vacuuming of the panels and the AC sucking out the room humidity/moisture to do the trick, since cadence had no suggestion and/or solution other than to send the panels back and get them re-foiled as a last resort. my friend, not being so adventurous, still is facing issues. we also took our (disconnected) panels to another old foil owner. his ES panels were working as magically as ever, monsoons, humidity notwithstanding. our panels on his connectors would not budge either (leaving out the possibility that the xOver, connectors, power, etc., in our speakers were the issue).
as a matter of fact, there is an FAQ on the ML site on ES maintenance. has a lot of valuable inputs, though some are quite atrocious.
i suggest one covers the panels with a material that keeps the humidity out (so cloth MAY not be a correct suggestion for this as it absorbs moisture and would render the area around the panels dank).
also, i can't agree to the 'immune to moisture' bit with the new foils, though that was the original claim.