Kevin,
My room is way too small for the 3.7s if using any kind of typical logic.
...but having said that, with a bit of experimenting, the 3.7s now absolutely disappear. The sound stage is wide, deep and layered. A good test is with Qsound recordings, where it's uncanny how sound can appear to be located directly to the left or right of my head.
Problem is that now, with the 20.7s on the horizon, I'm figuring that they'll be even better in my too-small room.... your math is unfortunately perfectly accurate.
