Originally Posted by kgrlee
What's your real life experience with NO DUST COVERS?
I've heard one pair of ESL63s with no dustcovers and they did have less of the mid/HF delayed resonance that is their main audible fault.
But Peter Walker said they would need cleaning or even new diaphragms after a month .. sometimes after a week.
Obviously environment would dictate how long the panel would last without a dust cover. I get a lot of quads in with pretty grimy dust covers and the panels inside are pristine; except for the fact that the glue or diaphragms have failed. The dust has to get to the dust cover through the grille cloth and grilles and it still does.
Certain ranges of the quad 63's had extra bridge pieces with dacron that pushed on the middle-ish of the dust covers. I should do some measurements of a 63 with the plain dust cover and also with those funky things on them.
Also the newer ESL's and the early 63's have tensioned dust covers , while the majority of the 63 production run had loose dust covers in my experience. You can tell by picking one up and moving it around and you'll hear a woosh woosh noise of the loose dust cover moving around.