DSPeaker Dual Core 2.0: Tips and Tweaks Wanted

I have longstanding problems in my listening room (read: NYC apartment) with room modes that reliably produce horrendous booming bass at some frequencies.  I have worked with speaker positioning to the extent that I can, but because it is a NYC apartment, space is at a premium and I can't solve the problem this way.  I've added bass traps and tried to treat the room in other ways, but still: boominess. This happens whether I am using the tiniest of monitors or large floorstanders, front-ported, floor-ported, rear-ported or sealed.  It is aggravating and actually starting to drive me a bit crazy.

I finally gave up and acquired the DSPeaker Dual Core 2.0 about a year ago, a nifty little unit that has removed the boominess and left me with tighter, firmer and more controlled bass.  But I have a nagging feeling that the unit is also robbing my music of some "air" and "life"; that is, while the bass is much cleaned up, the entire rest of the spectrum sounds duller and a bit more recessed.  And I don't think this is just me "missing" the boomy bass I had before.  It has bothered me to the extent that I keep trying to remove the unit from my system, but then I am left with uncontrolled bass that simply won't do.  I understand that this is a trade-off, but I want to learn how to maximize the results I can get with this unit in my signal chain.

I'm interested in hearing from others who have this unit as to how they have achieved optimum results in the context of their own systems.  Do you run it in between the pre- and power amps?  Between the DAC and the pre?  Do you use the typical calibration or have you found better results by limiting (or extending) the frequency range the unit modifies?  And also, I'm curious what level people set the volume of the unit at.  I have the DSPeaker running between my DAC and the preamp and I'm not sure what level I should be feeding the preamp. 

Any other thoughts, suggestions, comments or complaints about your own experience with this unit are welcome.  I am looking to commiserate with those similarly situated.  I need to solve this problem!!  Thanks!