I am trying to make a room that is not helpful at least to sound reasonable. It is 9' wide (with a large window on one wall), with an 8' ceiling, and about 40' long with a few minor arches and windows along the way. The last dimension I think is irrelevant for these purposes. The floor and ceiling are wood nailed to joists, and the walls are standard drywall. Along the length, at 17' the floor changes to porcelain tile and the room opens up, but again I don't think this is significant.
The loudspeakers are Beveridge Model 3s, which are cylinders of about 2' diameter and 6'6" tall. They are a 6' electrostatic line source that terminates into an acoustic lens that gives it about 180 degrees polar dispersion which is pretty uniform though slightly biased to the on-axis plane; the back wave is damped. Their top and bottom have rather flatulent 10" sealed woofers, and the bottom one is slot loaded. A traditional way to set them up is to have them face one another, though other orientations work fine too. Yes, the room is too small for them, but that's what I have to work with.
My initial thought was to put a heavy curtain on the front wall behind the speakers, put a rug with a thick pad on the floor, some tube traps in the corners, and play with the speaker orientation (rotation) with absorption or dispersion at the first reflection plane. Likely some ceiling treatment will be needed.
I have a minidsp 4x10 that I intend to use to help with the mess that the nearly identical room dimensions will make, but I'd like to try to do as much with the room first before using the filters. I use REW on a near-by computer, a calibrated microphone with a Focusright unit to provide phantom voltage and to provide a USB signal to the computer. I'm comfortable with all of that.
I know the room/speaker combination never will be outstanding, but at the moment is really is lousy. Advice would be appreciated.