Quad ESL 63 in smallish room ?

Squezzing the 63's between 2 wall being 11' 6" apart is probably not adequate.
Even thought they are at a respectable 5 feet from the back wall and that the listening position is a nice 8 feet away, I still think they could do much better in a larger room ,.. what do you think ? thanks Pierre
for a similarly transparent sound with much better dynamics and bass with no beaming try the carolina audio jtm's. I longed for some quads till I heard these... they work great in every room I have heard them in for 12 by 13 to 24 by 30.
Well, 11.5 ft isn't too much but it could work. They can be placed close the side walls without creating destructive lst reflections. You don't specify how long your room is so I can't comment about the "5'out" set up, but it does sound as if your listening position may be too distant for good soundstaging. Have you treated the backwall reflections? Are the speakers on stands or on the floor. What are your sonic priorities? What about your present sound do you dislike? Give us more info - maybe someone here can help.
No problem.
"Beaming" is not a bad thing with Quads! All electrostats do that, due to the nature of the drivers.
Like Newbee touched-upon, Quads don't spray "highs" all over the place like a tweeter, so they can be placed next to a side wall.
In fact, 11 feet may probably be too far apart, depending on your listening distance and toe-in. (the five feet from the front wall is a good thing) They're certainly easier to deal-with in a limited width room than other types of speakers.
I used to have a pair of 63's in a roughly 12 by 12 foot room, and I've also used them in a 13 by 31 foot room. Of course they liked the big room better, but were still quite enjoyable in the small room (though I had to pay a lot of attention to addressing early reflections).

If you have five feet available behind the speakers, then chances are you'll have very good depth of soundstage (assuming you can diffuse the backwave - I use fake ficus trees). Despite their directionality I think you'll still want to treat the first sidewall reflection zones, as that will reduce your awareness of the walls' presence. Once again, I prefer diffusion over absorption, unless your room is overbright. And even then, be careful not to overdo the absorption - a little goes a long ways in a small room.

Having the speakers a good 5 feet or so out in the room is also good for the bass; with a dipole, the bass is reduced by proximity to the "front" wall because it's the out-of-phase backwave that's being reinforced. If you need to improve the bass, move your listening position closer to the "back" wall (the one behind your chair). Bass traps in the corners behind the Quads can also increase the bass because they're primarily absorbing the out-of-phase backwave.

Best wishes,

Quads need room to excell period.If your sitting only 8 feet away you be better off buying a good pair of Stax headphones,same effect...5' from the back wall,2'from the sides,at least 10' from the speakers is the minimium requirements to get the most out of these wonderful speakers,if you room is low and tiled no room treatment on this planet will control the standing waves.
Thanks all !
Bmwhaus, maybe you could explain about the nature of the standing wave element you mention, and its relationship to sound quality.
No tiles and hight ceiling (12') in my room, but anything else goes against getting the Quads to deliver what they really can. There's furnitures here and there in close proximity and if the speakers where at a distance of 2 feet from the side wall, the distance between the 2 panels will be about short 4 feet.
There in storage right now, but my feeling goes towards the minimum requirements proposed by Bmwhaus for optimal result and althought I still could sit at 13 feet from the speakers, there still would be a low profile sofa and table in between the distance separating us.