Foam bass traps and diffusor panels

Now that you've adjusted your speakers, try adjusting your listening position - you may be sitting in a bass node of consequence. Re bass traps - the efficiency of any bass trap will depend on the frequency at which you are experiencing the rise - if the frequency is low enuf, forget it, you won't be able to control it except by using a parametric equalizer. I'd recommend that you really do some research into the issue of controlling bass before you start buying materiels/devices of any sort or you risk wasting some serious money. I didn't check out you room dimensions but from the size it doesn't seem as if you should have such serious problems. You might pull up Rives site and his computer model to see what location it recommends for placement of your speakers and listening position.

Now I understand more of your problem. You have undoubtedly dimensional induced bass standing waves. Have you done a check with a sound level meter (Radio Shack) with a test disc (Rives is adjusted to the RS meter) to find out where your bass rises and suckouts are? And, more importantly how broad or narrow they are? When you measure at the listening position remove the chair and walk back and forward a bit and see what happens (ditto for the speakers) - this will help you ID which frequency is, or might be, problematic because of seat/speaker positioning, and which frequency is a room node problem (as that won't change much with speaker/seat changes. Its the pits - I've got a 9db rise at 32 hz that I just can't get rid of so I feel for you.

Well, FWIW, Rives places my speakers within a few inches of where I had already located them by ear/meter/disc - I didn't move them. His program had the seat a foot more forward than I set it, coming much closer to an equalateral triangle. I have found with most speakers I prefer something closer to a 11 to 10 ratio with the speaker being further from the speakers than the speakers from each other. For me the process was (1) finding good basic imaging, (2) realigning seat and speakers to get the bass as flat as possible, then (3) fine tuning the imaging over a period of many months - no more than an inch at a time, with a considerable intrim period between movement. Slow gets it done right - at least thats what the turtle thinks. Let us know how it works out.