Subwoofers masking other frequencies.

My initial guess is that it's an integration issue, and that the subs are contributing too much energy a bit north of the subwoofer region.  

Make sure you aren't using the LFE inputs, unless you are using a home theater processor.  And even then, you might want the additional roll-off of using the normal music inputs.  

I suggest reducing the lowpass filter frequency on all of your subs to the minimum, which looks like 50 Hz for the SVS B2000.  That may still be on the high side, given that the lowpass filter slope is only 12 dB per octave.   

Then adjust the level control, which will make a big difference, and then the phase control, which will probably make a small difference.   Cycle back through fine-tuning a few times.  The level control may take a long time to dial in, as very small changes in sound pressure level make  disproportionately large changes in perceived loudness at very low frequencies.   

You can go back and try raising the lowpass filter frequency after you've gotten the level and phase dialed in, but if all three of your subs are the same SVS model then the 50 Hz minimum might end up being your best bet.   

Duke

Duke 
What should I expect from the adjustable phase knob. Vol. Increase ? Smoothing of tone?
Thanks for the help.

 The phase knob mostly affects the blend between subs and mains.  When it SOUNDS right, it IS right.  There are too many variables to predict in advance what the "right" setting will be, but in the end what matters is how it sounds.  Don't be afraid to make big adjustments.   

Duke

I took your advice and set the crossovers to dead bottom and slowly increased volume  winsome good results. 
Thanks for your help Duke

+1 audiokinesis