Actually I see that doesn't have any XLR inputs. On the Focusrite Scarlet 2i2 I see XLRs but no RCA inputs. So seems like that one would not work either? The Motu M2 2x2 has both so would that be the way to go?

 

That could work. Just be careful of input levels as you'll fry those soundcards if too high of a signal goes in.

I used to use a motu m4 and it was great. I have a bunch of rme boxes at work, but usually I use the jl max or audio precision these days with the max being easier and quicker. But they can accept very high voltage ins as they were designed for that purpose. Those sound cards were not.

But you should be fine because you can go out of your dsp into the sound card and see all that info that way. Just make sure absolutely zero eq is on your dsp so that the signal is just straight pas through.