You are showing the spectral decay. The ringing is less, as expected. A steady-state measurement might show a sharp null becoming a wider trough, or might not in this case.
Seeing the volume of Ethan's posts, I'm guessing that I won't get the last word in. So I'll say one last thing (on topic) and bow out:
Electronic correction is not worthless. If you're willing to hold your head in a vise, you can get excellent sound for the cost and aesthetic impact of software. With some room treatment, and careful tweaking of the software, you can achieve really good sound across a wide listening area.
-Ben Loftis
Studio Outfitters