Room correction with D400 and B&W 800D

[Soniclife]

Ive been using REW to analysis whats going on in my room as I've been trying out various acoustic treatments. Overall I've got a significant improvement in SQ, but I'm also quite puzzled by the results I'm getting with SAM.

I'm running 10.0.5 on O d'A's through Sasha 2's.

The green trace is with SAM set at 100%, the purple is with SAM on but set at 0%. It's interesting how, at least in my room, SAM@100% it creates a huge subsonic peak around 15hz.

Is that a near field measurement?