I do have about 10 dB lulls at about 56 and 78 Hz, which was the same pattern no matter where I put the sub, so it has to be my room. According to SVS's graph the sub does dip a bit at these points, so that probably contributes a bit as well.
One thing I did find odd, was that I am down a decent amount as well at about 95 - 110 hz... I don't know if this is just from coming out of the range of the sub, which level was probably set a bit too high, but I don't really have another explanation for it as the W22's should handle that frequency with ease.
I think the next step is going to be a couple bass traps in the back corners of the room and maybe some panels on the walls. Can't hurt I guess.
As I was saying, you get the hole around 60 Hz from the length, and the 93 Hz because of the width. It isn't only the sub's bass which is affected by the room. Any bass which is produced will interact, even that from the W22s. Oh, and an 8 foot ceiling is contributing one more major room mode at 140 Hz.
Definitely start with traps, I wouldn't even worry about the wall panels unless they are nearly two feet thick, they won't be able to capture that low of frequency. Wall panels are used more to control treble reflections.
