Planar close to a rear wall? Quad for example?

FWIW, re backwave, in my initial frustration setting up Quad 63's I put heavy felt on the back of the speakers. As far as I was concerned all of the supposed benefits of using dipoles disappeared with the 'unmanagable' backwave.

The speakers didn't begin to sound good (open up and sound clear) until I got them out 4 1/2 ft from the wall behind them and using diffusing materiels was still very beneficial. In my experience the down side of the close placement to the wall wasn't just the loss of depth that was the problem so much as loss of clarity. But then I like to sit about dead center in an orchestral hall usually in rows D E or F where clarity is very evident.

Interesting how we all value the same things so differently.

Mr T my point was not to differentiate the 63's from the 57's, although not often spoken about, one of the huge differences between them, which is obviously not important to you, is the point source imaging nature of the 63's which is markedly absent in the 57's. The 63's were in fact one of the earliest electrostats or planar speakers to do this little trick. This exact feature may coinside with your 'rear of the hall' sonic preference because the 57's will always have a more blended sonic presentation than the 63's or later speakers as well as cone or horn designs.

What I was referring to was nothing more than what Duke has been talking about. The back wave needs greater seperation from the front wave than close wall placement will give it if you are seeking clarity. And, this clarity is what gives it a greater sense of 'depth of image'. I think it goes without saying, but I will anyway, if you like rear hall sound, clarity and its byproducts cannot be a big issue for you. I've never been in an orchestral hall where in the rear lower or upper sections I heard any direct sounds that were not greatly changed or influenced by hall size including reflections, reverberations, acoustic treatments, and the size of the audience.

Courses for horses. Or is it horses for courses. :-)