I think I need more bass traps, where to place them??

Soffit traps, from GIK Acousitcs, you can run them on all 4 sides of your ceiling.

However, two tips:

1. Place your speakers asymmetrically
2. Get an EQ.

Since you have bass traps, controlling the room nodes is going to be a lot easier with an EQ, you are no longer in the realm of "impossible" peaks and valleys.

Best,

Erik

Talk with the gents at GIK.  They are pros with this stuff and can save you time and effort with their expertise.  They are very helpful.

It would help considerably if you located the standing waves and reflections in the room using a test tone on a CD or record and a sound pressure meter. Trying to find the ideal locations of multiple tube traps is a lot like trying to solve three simultaneous equations in four unknowns. As fate would have it oftentimes the standing wave one is attempting to address with a tube trap is not located directly in the room corner but say a foot or two away from the corner.

There are also room resonance calculators/simulators on the 'net. You put your room dimensions into a form, and a three dimensional depiction of where standing waves are produced in the room will be displayed. That is where bass traps should go. An active electronic unit designed to deal with the problem, like the DSPeaker Anti-Mode 2.0 Dual Core, can also be of help.

Thank you for the post guys and sorry for not being more clear. As @onhwy61 mentioned my room is almost a cube at 10’ l x 9’ w x 9’ h. Note that the back wall behind me is 36" tall, above which the space opens up to my family room and kitchen. Because the room is almost a cube I cannot tell from which dimension the axial mode is coming from.

I know that my Right speakers has peaks at 60/120/180 and since I sit with my back right against the short back wall, I have to believe this is being caused by the length axial mode which has max volume of all the modes at the extremes. What I dont understand is if I want to try to address the length axial mode should the bass trap go directly behind the speaker or on the back wall behind the seating position?  Even though the back wall is only 36" tall, it is only about 2" lower than my ear height.  

@geoffkait I am not sure I understand what you are suggesting. I measured my room response only from my listening position so isnt this where the wave is?

@erik_squires and @bdp24 I do use EQ with REW. I found that peaks are dealt with effectively with EQ but dips do not improve much.