Frequency Response

I’ve recently started measuring my in room response and it’s become an entirely new learning process.  I’ve become slightly obsessed with smoothing out the in room response as much as possible through speaker placement and room treatment placement.  
Anyhow, I’ve got a dip in the response from 330-400 hz at my listening position.  The dip is not there when I stand vs. sit in this spot.  I’ve tried moving the speakers all over and I’ve tried fixing it by moving my acoustic panels around but I still can’t get rid of this nasty dip...

Does anyone have any other ideas I can try?  Has anyone here had similar issues with your room cancelling out certain frequencies higher up than the bass region we are usually talking about and what did you do to overcome them?
Sounds like a null related to chair location and room dimensions. Try moving your chair backward or forward 6 inches (more or less) and see if the frequency amplitude changes. 
It might be floor/ceiling  bounce, but try throwing a blanket on the floor between yourself and the speakers as an experiment.

Also, I _highly_ encourage you to consider your ceiling when you can.


@newbee, definitely a null...  I just difn’t know or think that they happened above 100hz or so.  Never thought abkut hugher up frequencies cancelling themselves out.  Makes sense though.  I also didn’t realize how high of a pitch 300-500hz is.  
I tried some really big differences in speaker location and speaker height, even flipped them upside down and measured the freq. response.  Interestingly it didn’t change much.

I always knew the room makes a difference but now I am really beginning to see how much of a difference.  Its great to actual have a visual of my freq response now.
Anyhow, Im hoping to tame this and some other areas with more room treatments.  Maybe in the meantime I flip my listening position and see what happens 🤷🏼‍♂️