Adjusting bass without adjusting bass!

If you have room to move the speakers out and away from walls that would be the first suggestion. You can also look into adding bass traps to the room. These can be as simple as a bookshelf loaded with books against one of the walls. I assume you are not using a subwoofer?

Actually, adding bass traps may increase the apparent base as it cleans it up and you get less cancellation. In theory. Slabs are of no use at all. Just as worthless as the spikes sonically. Spikes do make then more stable on carpet. I wonder if you are just not accustom to the base that should have been there all along. Monitor's are quite good.

Ugly: reverse the phase to one speaker. You will get less bass!

One of the major issues in your setup is that your listening position is against the rear wall. This specific setup will cause you to have too much bass ringing. The best solution, and perhaps, only passive solution is to move your listening position away from that wall.

This solution costs 0$. All other solutions that may work, albeit no where near as well, will cost 100's$ if not 1000's$.

The first step to correcting acoustical problems within the room is to ensure proper setup of listening position and then speakers. After this, acoustical treatments then digital equilization using time domain-based software.

I was going to suggest moving your speakers, and you listening position further away from the walls. But you ruled that one out. How about headphones?

Good suggestions on the listening position. I have noticed a dramatic difference in bass response just by moving my head away from the rear wall just a foot or less.

If the bass aserbated generally it's all about the positioning. Most audiophiles use audiopoints to transfer resonant energy stored in the cabinet. Star Sound, Black Diamond, Mapleshade sell them. I have seen lead, granite and concrete used before and the results are mixed. I had a pair of Meadowlark Audio Ospry speakers on audiopoints atop granite and it sounded sterile. I removed the granite and just used the points and two weeks of settling in the bass was tight with a beautiful mid bass punch that didn't crowd the midrange. I prefer Star Sound though I have been a Mapleshade dealer in the past.

Go to the Mapleshade website and Pierre Sprey(F-16 and A-10 designer) has a page of advice and addresses positioning.

Here is one of the free tips from Mapleshade

" For much improved bass and huge soundstage, put your listening chair or sofa right against the wall behind you. Move your speakers in to 5' in front of you and 7' or more apart. No room treatments will yield this much bass improvement"

Pretty much everyone here at AVS has mentioned that back wall is the worst listening position!

You certainly have to move the speakers away from the wall. If the speakers didnt come with port plugs, you can close the ports using a piece of foam. You can buy a piece of foam from Joanne Fabric. If you completely close the port you would lose a lot of bass. You can try using a piece of foam smaller than the port so that you only partially block the port.

BTW are you playing compressed music or loss less format.

If you hear boominess (reverberations) then bass trap is a very effective best solution. Owens Corning 703 panels piled up in corners in the form of triangular pieces is a very cheap solution. That is what I have done. Things like BFD (Beringher Feedback Destroyer) do add distortion to the sound in my opinion, though they let you tweak the bass. I tried that but they just cant get rid of the boominess. BFD is basically an EQ with a lot more freedom than a fixed 6-band EQ. But no amount of EQ will get rid of the boominess or reverberations unless time based correction is added. You could try products that do such thing but they would cost more than the MA speakers. I spent under $100 in adding the Owens Corning 2inch thick 703 panels as bass traps at the corners of my room. I have some panels left. I have to fill the rest of the corner (top 1 foot or so).

You can go to the HT development forum and there is a long thread on bass traps.