Planar close to a rear wall? Quad for example?

If you can completely absorb the backwave, it would probably work. Unfortunately I don't think that's realistically possible. The problem is, the two-foot round-trip path length difference (imparting a 2-millisecond delay) before the backwave energy arrives at the listening position puts it right smack in the time zone where the ear is most sensitive to coloration and loss of clarity from reflections. On the other hand, 10 milliseconds of time delay (corresponding to Sogood51's five-feet-out dipole speaker positioning) is long enough that the reflections will add richness and liveliness with minimal detriment.

I build monopole and bipole versions of essentially the same speaker. If I had a customer with the same positioning constraints you have, I'd advise him to go with the monopole version. That would be my advice to you DrKen - go with a monopole speaker for now. I don't think Quads or other dipoles are going to work well for you.

Duke
dealer/manufacturer

MrTennis,

Come to think of it, the original Quads have a felt pad that absorbs the tweeter's backwave. Hmmm... I hadn't taken that into consideration, but that would probably give them them a much better chance of working close to the wall than other dipoles.

As for designing an electrostat to compete against the SoundLabs, well thanks for the vote of confidence but that's out of my league!

Duke