It could be that you are getting what's called first reflections from the right and secondary reflections from about the left corner, meaning that the sound has reflected off the right wall, then again off the left wall and to your ear.
The standard way of finding where reflections will come from is 'the mirror test'. You sit in your listening position and get a second person to move a mirror on the right wall until you can see your speaker drivers. That is the first reflection point. Another way would be to draw an accurate plan of your room with speaker and ear positions and draw a line from the driver to your ear so that the angle it hits and reflects off the wall is the same. Here's one I did in 2013:
View attachment 165065
You can then look at reflections off any wall from any speaker. Remember you might also hear reflections from the left speaker coming off the right wall to your right ear.
Wall reflections are a contentious issue. I've tried to cancel all mine and find it gives me a precise image with clear instruments and vocals, but that image remains only between the speakers (unless there is some peculiarity in the recording). Others like the wider image that reflections might give. Psychoacoustics (how the ear and brain combine to allow you to 'hear' things) comes into play here too.
Moving your ears (sofa) will not only effect reflections but also the bass. Play a bassy song, or perhaps a single bass tone, and walk round your room. You should notice that the tone sounds different in different places. Not only that but if you move your head to the floor or to the ceiling it will sound different there too. That leads to the important conclusion that positioning of ears and speakers is a way of changing and perhaps improving how bass sounds. Of course you may be restricted on positioning because of your domestic circumstances but it may help. If you can add a corner bass trap here and there that would help too. Then what can't be corrected by that can be altered with subs or DSP/EQ. Here's a test tone CD that is useful:
http://realtraps.com/test-cd.htm
Then look at the higher frequencies/reflections. Reflections can be altered perhaps by speaker positioning and/or toe-in, stopped by panels (art panels maybe). You can't stop reflections with DSP/EQ but you can use it as a kind of tone control adjusting large parts of the frequency range to your taste.
The ultimate solution is not found in measurements - these are just tools - but in what sounds good to you.
