What are ways to fix speaker dips in my speaker or audio room

Soundwise it is counter-intuitive to place the speakers along the long wall.  I read in a recent review that the 10 best sounding concert halls were all rectangles with the orchestra at a short end.

You have a good size room but the speakers should be placed well away from the back wall (especially dipoles which need 6 feet ideally).  You should not sit too near the other backwall either, or you receive bounced signals off the backwall that at some frequencies are out of phase with the signal direct from the speakers.

In your room as it is if the speakers are six feet from the back wall and you are six feet from the other backwall then you are sitting six feet away from the plane of the speakers which is too close.  So you call in an engineer to advise you about all the room treatment you need.

If you can change the orientation you should do so.  You will need much less room treatment.

What happens when you swap the speaker leads?

Is that your room in your profile picture? Lot of glass? Have you tried the test with the PS Audio power removed?

Use the short wall, as mentioned. If you're not open to that. Try a few things to that should help regardless. Looks like you have tile floors. Place another rug (long and narrow) along the front wall where your speakers and amps rest...from wall to wall. Rugs/softening the room at the boundaries helps a ton.

That cleaned up the bass response in my room. I also bought a bigger central rug. 

Maybe you should purchase new speakers or hire a different sound engineer.