Electrostatic Speakers Vs. Horn/component Tweeter

Ive had a pair of ML ESLs for a few years now... No problems... The panels crossover to the woofer at 500Hz... And the woofer goes down to 42Hz... I would set your AVR to a full range and cross over the subwoofer itself at around 52Hz... So if you are doing a "small speaker" crossover in your AVR your most likely doing things wrong... You can try to run the ESL at another ohm setting via your AVR 2, 4, 6 or 8 and see how that changes your thermal issues or add a 2 channel Amp... These ESLs will test your AVR or AMP diving into low ohm territory... Standard AVRs and AMPs will want to double power as ohms half and ESLs "map" opposite of standard speakers...  Are you bi-amping or bi-wiring???  Sounds odd to me if you are driving it all from an AVR...  If I were to bi-amp I would use tubes for the panel and solid state to drive the woofer...

BTY you can vacuum the dust off the panels... RTFM...

It might help if you clarify which ESLs you have...  I have the original Motion ESLs...  Did drive them with a Yamaha AVR...  No thermal issues...  Now drive them with a small McIntosh MC152...  No problem with those autoformers...  You might want to find an AMP that "maps" to your ESLs and does not just double as ohms dip...  As those ESLs will dive into the lows ohms at high frequencies, unlike orthodox speakers which dive towards low ohms at low frequencies...

Ok... So, crossover between panel and woofersx2 at 400Hz... I don’t think I would try and bi-amp with an AVR like that... You could be pushing 150 watts x 4 just for RMS... And when panels dive to 2 ohms your pulling 150 x 2 per channel (std) for the woofers and 150 x 3 (8, 4, 2 ohms with a doubling AVR/Amp) per channel... Ouch!!! No wonder you would have a thermal problem and clipping... Wonder what the total wattage output of that AVR can handle is... Spec is 150 watts per channel in _Stereo mode_ I read that as 2 channel... And I don’t see anything about multichannel mode... Also not sure how you would drive 2 left and 2 right stereo channels to bi-amp from an AVR like that... And how would driver time alignment work out... Speaker placement and time alinement is critical with these ESL hybrids... Hoping you have your room acoustics in order and use something like REW to get your speaker placement and room right...

This is always a good read when considering amplifiers for ESLs...

http://www.atma-sphere.com/en/resources-paradigms-in-amplifier-design.html

For stereo music a proper line stage preamplifier is always the best way forward...  And of course the proper paradigm amplifier for the type of speakers used...

Good luck in you choices...

ML suggests a power amplifier in the 20 to 400 watt range... I think they should do just fine with 150 watts... Although the ESL X are rated at 6 ohms which will cause your AVR to run up 190 watts per channel... Again more than enough to properly power your ESL Xs...

Back to you initial question about how your speakers may be damaged... The mylar may decompose with age, sun, dust... There is no voice coil like in a cone speaker which may deform or melt in an overpower situation...

I would be curious how the ESLs sound running as a vanilla 2 channel with out that extra subwoofer and set as large speakers in the AVR... You may be able to connect that subwoofer to other left and right channels or even tap directly to the standard left and rights... There is no reason to run them as anything less than full range speakers... You could then crossover your subwoofer in your subwoofer, given it has the capability to manage its own gain, crossover and phase or polarity...