Bass Response

Thank You All
There are more bass at standing position or on the sides along th ewall. I meant so much more bass which create a much more fuller sounding.
I've tried to move speakers without any affect, moving listening position closer to back wall improves bass response at listening chair position but not as good as at standing position.
I don't know if i need the address the issue through the use of ceiling treatment E.g. ceiling bass trap or diffusers
Room: 6 meters x 5 meters x 2.4 meters (L x W x H). Speakers are placed along the width of the room.
Gear types: Wilson Sophia 3, McIntosh MC501, ARC Ref 3, Esoteric K03, Weizhi PRS6, Shunyata Hydra 2, Lessloss Sig PCs (amps), Stefan Audio PCs (cdp, pre), Nordost Quatro Fil ICs, Grover SX SCs, Finite spider racks, Vibrapod cones and dedicated power supplies

I've done my simple mod calculation but really have no idea where are the problems or how/ where to apply acoustic treatments.
Appologise for this as i'm new to these acoustic treatments. Your helps will be much appreciated

L 19.7
W 16.5
H 7.9
Cu.Ft. 2567.895
L-1 28.68020305
W-1 34.24242424
H-1 71.51898734
L-2 57.36040609
W-2 68.48484848
H-2 143.0379747
L-3 86.04060914
W-3 102.7272727
H-3 214.556962
L-4 114.7208122
W-4 136.969697
H-4 286.0759494
L-5 143.4010152
W-5 171.2121212
H-5 357.5949367
L-6 172.0812183
W-6 205.4545455
H-6 429.1139241
L-7 200.7614213
W-7 239.6969697
H-7 500.6329114
L-8 229.4416244
W-8 273.9393939
L-9 258.1218274
W-9 308.1818182
L-10 286.8020305
L-11 315.4822335

I tried panel bass traps (Gik 244) in the front corners and like yourself wasn't satisfied with the results. The addition of Acoustic Science Corporation 16" Supertrap Tube Traps in the front corners was a huge improvement in bass management!!! Your speakers appear to be close to the back wall, how far away are the outside rear corners to the back wall? Side wall? Try playing a record with acoustic bass, I like Ray Brown's "Solar Energy", move the speaker away from the front wall in small increments until bass becomes light, I use rear outside corner for measurements this allows changing toe in and not changing distances. Now start moving towards front wall in small increments until you like the definition and size of the bass, did this move the null and improve the overall balance of the sound in the listening position. I didn't mention the side walls or toe in adjustments to keep variables to a minimum for now.

Thanks Samhar
The speaker outside rear corners are about 3 feet away from the back wall.
I've tried Cardas speaker placement method last night and found that it made very little difference in the bass response at the seated position.
I've also bass tested using Jennifer Warnes Deep Way Down song. There was plenty of bass at the seated postion which make one thing that an active sub is running in the room. (Very nice, I like it!). However, with certain songs, the bass is still flying half way height in the room.

Updated Mode Cal base on precise room measurements...
Can someone please explain what are the main issues in my room and recommended treatment methods? It seems there are freq. jumps on H values
Your help will be much Appreciated!

L 16.08 H-4 287.1664549
W 14.1 L-5 175.6840796
H 7.87 W-5 200.3546099
Cu.Ft. 1784.34936 H-5 358.9580686
L-1 35.13681592 L-6 210.8208955
W-1 40.07092199 W-6 240.4255319
H-1 71.79161372 H-6 430.7496823
L-2 70.27363184 L-7 245.9577114
W-2 80.14184397 W-7 280.4964539
H-2 143.5832274 H-7 502.5412961
L-3 105.4104478 L-8 281.0945274
W-3 120.212766 W-8 320.5673759
H-3 215.3748412 L-9 316.2313433
L-4 140.5472637 W-9 360.6382979
W-4 160.2836879 L-10 351.3681592
L-11 386.5049751