I'm building a desktop system and would like a moderate-high quality DAC to use for processing between the amp and PC. I can use software on the PC for EQ, I've had nothing but problems with miniDSP and I'm just hoping at this point they will RMA it...I was originally looking at the RME AD-2 but it doesn't support 2.1, which is why I ended up going the miniDSP route.
I use a multichannel audio interface (Focusrite Clarett 4Pre) and a DAW (Ableton Live) which came free with my Clarett to process signal from my SPDIF streamer. In Ableton Live, I apply simple digital EQs to 3 output channels - one to sum the Left and Right channels for my subwoofer and second & third to roll off my mains starting around 80 Hz (in my room this seems to work best).
If you're planning to use your computer as the source, it may be trickier as you may need to create a virtual sound card. I was able to do this previously using Soundflower (I believe) on my Mac but when I recently tried it didn't work. I don't use my computer as the source so I didn't spend time trying to fix it.
If I had to do it again, I would purchase an audio interface that lets to change settings of device directly rather than using a software. You also miss out on a wireless remote but I control volume from the Tidal app on my phone. The Clarett sounds terrific 95% of the time on the mains but I'm planning to purchase a 2 channel DAC that will be able to take SPDIF output from the Clarett. I run everything balanced and my system is silent.