Actually what am I saying, JRiver can be made to work with everything in Windows and accept an input, just like what I said earlier. Downloaded the trial. It looks like there's some serious DSP functionality there. Why didn't I at least check this out before brushing it off a few years ago???
OK, time to go back to PC DSP. I have a spare MacBook Pro that is perfect for this task. No need to even spend $500 on an Intel NUC, although I kinda want one just because they look slick. But then, a MacBook setup might look slicker since it looks like the external USB sound card is the only piece of equipment powering the speakers. I'm gonna do this at least until I get a Sharc DSP working, which might take some time. Even then a PC would be useful for experimentation since it takes VST plugins.
I like where this is going! I was dreading the huge wiring mess from having 4 miniDSP's and the potential for time sync issues.
Only thing is there is exactly one 7.1 USB sound card on the market I can use, the Asus Xonar U7. I wish there were a few more choices. I'm not a DAC guy or anything, but I kinda wished it had an optical input so I can avoid 2 unnecessary DAC and ADC steps for the input I want to use. Apparently it doesn't work well with Windows 10 as well.