DUNLAVY SC-VI

I think you want the speakers firing away from the short ceiling side so that reflections are not "focused" on the listener by the ceiling, but I don't have any empirical acoustical data to back that up.

Alissatweaks, That's what I thought. With that in mind, is there a reason the room is 20' X 20'? Doubling dimensions is usually not the best way to go. I don't share your disdain for audio processors, and with those dimensions, such a piece of equipment might be helpful. I agree with Daverz that firing the speakers from the short ceiling side might be preferable, with that in mind the Dunlavy SC VI's height might be an issue.

I, similarly to Pryso's friend, had Duntech Princesses in a 20 x 18 room with openings going out from the back side so it presented a larger acoustic space, and I think that was the most a room of that size could handle (I tried the Duntech Sovereigns, equivalent of the Dunlavy SC Vs, and felt they were just a little too large for the room). I think the room size you are talking about might be better suited to the SC IV or possibly the V. Part of it is the distance you need to sit back from the speakers for proper driver integration as Pryso notes, the other is bass loading in the room. And I agree with others above, try to avoid a square room if you can, since it is being built. The VIs are a great speaker system, but I think to hear them at their best you might need a slightly larger room or some room equalization to tame the bottom octaves.

20x20 is a bad idea.

Here is some helpful info: http://www.cardas.com/content.php?area=insights&content_id=41&pagestring=Listening+Room+Dimensions

OK, sounds like some options may still be open here so I'll jump in one more time.

Since you are/will be building the room, why square? If you are locked in to a foundation already constructed, look for ways to open the new room into an existing space to change the standing waves. Otherwise, if not too late, redesign the room.

Speaker choice -- I owned Duntech Princess speakers for 19 years and remain a big fan of John Dunlavy's designs. However, I never would have traded my Princess even up for a pair of Duntech Sovereigns for my 20' x 17' x 11' room. It is simply not large enough. I heard the DAL SC-VI only once, at the CES. But I also heard the Sovereigns in a multiple of rooms of various sizes. I would consider a room about 28' x 19' x 11' to be the minimum, AND I think the SC-VI may need something even larger to perform near their capability. With a room anywhere close to your stated 20 x 20 size I would look for Duntech Princess or DAL SC IV or IVA.

Good luck.