Reloading everything now results in a normal bass. I am utterly clueless as it seems to be a software error.
The worst part, miniDSP dev team is basically saying I have to allign the sub (already did), remove all loaded PEQ's (already did).
And, to make it worse: "Having never seen this behavior before on all our customers, we wonder what setup you have here. So please provide (..)" followed a few email later by "That's extremely odd as nobody else ever seen this issue on all the setups we have worldwide".
I understand that they want me to measure in DIRAC using a completely flat curve (only an XO), but I kindoff like to PEQ a bit first and then use DIRAC.
The device should be able to do this right?
Furthermore, reloading the same DIRAC filters which then actually works implies it really is the miniDSP.
Maybe it looses all output to the sub?
By the way I ended up with a 12 db/oct xo @70 Hz. I assume that does not overload the KEF's too much.