Using Two Dac Simultaneously

[agent_kith]

It's clear now the keypoint is mpd.conf
http://mpd.wikia.com/wiki/Configuration#Audio_Outputs
But how? That's the new question

That's where I will go first, as I reckon that is the easiest, but there are certain drawbacks, mainly because the audio output will not be in sync. But at least it gives you a PoC first step.

Once you get the PoC done, you may want to explore JACKd, or Pulse audio.

These two will do what you want. I personally think Pulse audio is detrimental to the sound, but I havn't tried JACKd yet. Look up on these two on the Internet, and see how it goes.

Technically you can use a computer and set it up as an active crossover. But it's not something I have explored myself.