The miniDSP SHD should not be used with MSO. MSO depends on the usage of mono bass -- that is, traditional bass management. But a proper implementation of traditional bass management has the "room correction"
after the point at which the multiple channels are summed to form a single mono bass channel, that is, after bass management. From the diagram below, it can be seen that the SHD's Dirac processing is
before the mixer. This means that the summed mono signal used for the bass depends, among other things, on the relative phase of the transfer functions of the Left and Right channel Dirac correction in the bass region, which is uncontrolled.
View attachment 117877
The SHD design is just fine for stereo bass, as in a pair of actively biamped two-way speakers. But MSO is not intended for stereo bass. In fact, the whole theory of optimization of multiple subs as originally written by Welti and Devantier assumes mono bass and traditional bass management. There are advocates of stereo bass out there, namely Griesinger, and I don't want to open that can of worms. Rather, I just wanted to warn users about incompatibility with MSO.
Of course, miniDSP will never admit this.