Get the HD. It has higher output voltage and iirc better resolution(more filters)
MiniDSP 2x4 HD, a USB DAC+DSP in a low cost package powered by a powerful Sharc 400MHz floating point DSP. The upgraded on-board 400 MHz Analog Devices SHARC processor also ena-bles substantial processing upgrades previously available only on more ex-pensive platforms, such as 96 kHz internal...
www.minidsp.com
If you scroll down, you’ll find the comparison table.
I would recommend making sure you can get the sub in the best location first.
Unless you’re space limited.
Also you’re gonna need rew and a mic to know what to fix.