new york city audio show 2018

@noromance, guess my memory is failing even more than I was aware of! I have a spare treble panel in front of me as I write, and it’s dustcover is clear. My Quads are actually still down in S. California, awaiting my next trip down. I put the stock grilles back on for storage safety, and not recalling the bass panels’ dust covers were gray, assumed they were the same as the treble ones. I ran them for years with the Crosby grilles installed on front, the stock on the rear (but with the burlap removed), due to the damn cat my better half refused to get rid of. It liked to jump up and hang onto the grilles, it’s nails protruding through the grille holes! It finally died, thank God.

@noromance Peter Walker said in an HiFi News interview that the felt on the back of the tweeter panel was to dampen a resonance problem around 2khz. And the burlap reduced back wave interference with the front radiation. HiFi News did a test with the 57's placed on 24 inch stands, with burlap removed. Sound quality was noted as more "open", particularly in bass/midrange. So I tried the same on my first pair, including removing the felt. Sounded quite good!

The last NY Audio Show I attended was back in June 1996 at the Waldorf. I remember the Wilson/CJ room sounding particularly fine!

The dust covers, rear damping is there for a reason.  Peter Walker knew what he was doing and I am guessing the man probably forgot more about electrostatic design, theory that most people will ever know.   

The rear damping is to control panel resonances.  Remove it you get a nice high Q whompy sound in the bass.  The tweeter panel will have a nice resonance around middle C you might like it!  I suppose aged way out of spec original Quads may sound 'better' with the damping removed.   The speaker does take a step backwards in performance.    But audiophiles can be prone to doing all kinds of things that are not a step in the right direction even though they think it is.  

Removing the dust covers is a very bad idea and produces little improvement in performance.  I listen to them both ways for testing purposes.  I can assure anyone the extremely minimal increase in performance, if any,  is not worth the long term reliability issues.  One only needs to look at the filth on the dust covers after decades of use to know they are a good idea.  I have seen plenty of 50 year old Quads that work nicely, not to spec any more but nicely, and the reason is those pesky dust covers! 

The grey paint on the front of bass panels is to eliminate glare.   Rarely when serviced are they painted again.  If they don't have grey paint either the dust cover has been replaced or the panel has been replaced. 

Sure Walker knew what he was doing, at a genius level. So why did he make the ESL with that horrid metal front grille?! It the panels have resonances, why is the front wave not as effected as is the rear?