I'm about to order one in place of Oppo controls. The HD unit gives you up to 80ms delay while lower units only do up to 7.2ms. One can also DSP up to 4 additional woofers. This also may have a place with my time and phase aligned speakers with the built in isobaric subs for full range music.
One can use Foobar 2000 and the USB input to get to DAC that will handle 24/96 do DSP for my upper 4-way array of drivers. This unit quite possibly would replace my linestage and crossover in that setup. I've done USB dacs before, but never liked them, but throwing in DSP of main speakers with even flatter response may be invaluable. If it doesn't work out full range still can use the minidsp 2x4 HD for the stereo subwoofers.
They also have units that work with hdmi but its lpcm so no go with our soundbar or my Xbox.
Would have loved to alter 5.1 before going to Xbox or K950 before upmixing.
I can't think of way to do DSP to the Samsung K950's subwoofer. The best idea I can come up with is to optimize its placement knowing the other dsp'd subwoofer(s) will make up the difference. Another crazy idea might be to not hookup the K950's subwoofer at all, replace with other subwoofers or do some mod as you've thought about in posts above.
The 2x4hd is ultra cheap because it doesn't have plug and pray automic calibrate. You measure and do that yourself with minidsp's mike. The OP in the referenced thread above gets into a lot of the budget ways to do things. If one wants quality plug and pray minidsp has a firmware upgrade for $200 that add their Dirac live solution. This does involve performance compromises... "If your 2x4HD is only used for SUB, it's not going to be useful to have Dirac". Also doing this Dirac firmware upgrade to take 2x4HD to their ddrc-24 knocks things down to 24x48.
The balanced unit is much cheaper and also excellent, but you lose delay capabilities (7.2 ms only). The unbalanced unit can only drive amps with strong input sensitivity of 0.9 volts or less as that is all it will output. 24x48 preferable for subwoofers, but these units do not have the optical input and only USB (not a big deal in my mind, but I guess optical can accept 24/96 if source will comply). For those wanting ultra low bass down past 20 hz. This company cross spectrum has the minidsp umik-1 mike with calibration file that gets you down to 5 hz (just sent them email to see if they still sell the file alone.):
There are issues with 24/96 with the minidsp with the really low bass so the cheaper balanced unit probably the best value for low bass: