Based on my experience your actually noticing at least 2 things.
First and the reason I often recommend that people get bookshelf speakers and a good subwoofer or two is that it’s often impossible in the real world to position a pair of towers for both the best imaging and the best bass simultaneously. If you move either your speakers or your seat then you change the dynamics of both.
The second thing I think your noticing is the chest thumping impact of mid bass, one of the reasons I’m considering getting:
MBM-12 Mid-bass Module Not only is that chest thump different than the deep rumbling bass it’s also directional which much better simulates the feeling of a real world explosion. To get that you both have to move a lot of air and have the drivers fairly close to you. In my apartment I sat only about 6’ from my M80s and had that impact at safe listening levels, but in my house the larger screen necessitates a wider placement of the L/R mains to maintain proper imaging with the screen. This in turn requires I sit further away 8‘-12’ (still experimenting) to keep the front soundstage from collapsing to the nearest speaker. Even at 8’ it’s getting to far away to get that chest thump I’m use to unless I pump it up to 100dB which is way louder than I’m willing to listen.
So while bass traps certainly wont hurt the mid bass and will certainly help overall you might want to consider trying something like the HSU Mid Bass Module if other tweaks don’t get you what you now know you’re missing. Now you also know why I like my M80 center especially when I could sit up close. The chest impact of the Balrog growling . . . .
