I think Rives' suggestion is probably an excellent solution.
Can you identify whether the midbass boom is in the region covered by the main speakers, or by the subwoofer? Does it go away when you turn off the sub? If so, then lower the crossover frequency of the sub and/or turn its volume down.
I presume you've experimented with speaker placement. Have you likewise experimented with listener placement? That can make as much of a difference as speaker placement does. Just walk around the room listening to the bass, and see if there's a region where it sounds natural. If so, try to make that your listening area.
I've had good results using speakers with dipolar radiation patterns in square rooms, as dipoles put about 5 dB less energy into the room's bass standing wave modes due to their figure-8 radiation pattern. If you ever do change speakers, you might consider dipoles (like Maggies), and maybe fill in just the very bottom with a conventional sub.
You might try re-orienting the system along the room's diagonal dimension (not exactly on the diagonal, but close to it, so that you're maximally staggering woofer-to-boundary distances). Also, I'd suggest you replace most of the foam with diffusion (I use fake ficus trees). That's an enormous amount of sound absorption material for such a small room, and in small rooms a little goes a long ways. What all that sound absorption is doing is soaking up midrange and high frequency reverberant energy while having no effect on bass reverberant energy, so it's making the room even MORE bass-heavy. It's working against you, I think.
Best of luck!
Duke
Can you identify whether the midbass boom is in the region covered by the main speakers, or by the subwoofer? Does it go away when you turn off the sub? If so, then lower the crossover frequency of the sub and/or turn its volume down.
I presume you've experimented with speaker placement. Have you likewise experimented with listener placement? That can make as much of a difference as speaker placement does. Just walk around the room listening to the bass, and see if there's a region where it sounds natural. If so, try to make that your listening area.
I've had good results using speakers with dipolar radiation patterns in square rooms, as dipoles put about 5 dB less energy into the room's bass standing wave modes due to their figure-8 radiation pattern. If you ever do change speakers, you might consider dipoles (like Maggies), and maybe fill in just the very bottom with a conventional sub.
You might try re-orienting the system along the room's diagonal dimension (not exactly on the diagonal, but close to it, so that you're maximally staggering woofer-to-boundary distances). Also, I'd suggest you replace most of the foam with diffusion (I use fake ficus trees). That's an enormous amount of sound absorption material for such a small room, and in small rooms a little goes a long ways. What all that sound absorption is doing is soaking up midrange and high frequency reverberant energy while having no effect on bass reverberant energy, so it's making the room even MORE bass-heavy. It's working against you, I think.
Best of luck!
Duke