I have a unique routing situation with my active crossover 3-way speakers + 2 subs and getting it to my 8ch Okto on Mac which I finally figured out. I'm still using the beta version that I was given for testing so this might not be necessary in the final release software. It should work for any multi channel DAC.
I created a 4 channel device in Rogue Amoeba's Loopback software and directed output channels 1&2 to Blackhole, 3&4 go directly to 7&8 input channels on the Okto. As an alternative you could use another 2ch instance of Loopback (paid) or use the (free) 2&16ch versions of Blackhole.
Which is routed into Dirac:
And then into
@mitchco's brilliant Hang Loose Convolver app where the XO separates the signal into woofer, mid and tweeter drivers. Dirac sends the sub content to channels 7&8 as shown in the first picture. Since Dirac is handling the XO between subs and woofers my filter set now only requires HP/LP filters between woofer/mid and mid/tweet. HLC will allow you to add more channels if you want for you crazy 7.4.4 people who listen to stereo content.
This allows me to create individual speaker driver corrections from near field measurements, then box + crossover points/slopes/phase and implement them via impulse .wav FIR filters before any measurement/correction for the speakers in pair or in the room is even considered via Dirac or any of the other DSP/DRC options out there. I'm using REW/MMM to measure and make corrections for those 6 driver then room measurements + rePhase to implement XO first to experiment with and I can instantly force my old sub/woofer driver XO with corrections to compare what Dirac is doing:
Seems to be working great. Previously attempts at sending the signal directly to the Okto from DLBC resulted in a undefeatable 7.1 configuration in Audio Midi Setup where my second sub would get a full range center channel sweep. This is a VERY unique audio routing scheme but maybe it'll help someone else out there so here it is. My theory is to give Dirac something approaching good to begin with and let it try to do some multi sub magic up to about 400Hz.
EDIT: for clarity, extra info and forgot to mention this allows for use of hardware volume control on the Okto and it's remote or using software/app. This is for system-wide audio processing or relegated to individual apps. I had come up with other solutions but this method uses the knob - long live the knob!