Did you run those sweeps with your subs on or off? Looks like they were on.
Subs were off. I muted all outputs in my miniDSP, so they weren't even getting signal.
Those are some pretty serious nulls for your front three to have, and right in the midrange. No bueno.
I no, rite? It sounds better than it looks, though (thank goodness). That one at 800Hz is only the span of a minor 3rd or so I'm guessing. I don't notice it.
Edit: Just to see what I was hearing, I generated a 10-second "chirp" sweep from 500Hz - 1.2kHz in Audacity. The sweep sounded the same volume from beginning to end, but it sounded like there was some phasing variation along the sweep. I wonder if that null could be coming from my HTPC and DLP TV cooling fans, causing cancellations, but I'm still hearing reflections in that range?
I've got an XLR mic, mic pre-amp + phantom power and a Behringer USB sound card that I could use for some time domain measurements to try and find out, but it's an awfully big pain to drag all that stuff out if I'm not unhappy with the sound. Eh, if it nags me enough I'll run more tests.