There's no DAC outside of the soundcards...everything is handled in software.
That image is old (and was just a test setup)...here is my current setup (with a different crossover)...
I decided I don't need an EQ, at least not until I run a white-noise or frequency sweep test...and the LS filter has phase control as well, so I got rid of the individual phase filters.
(Also note the sub output and VU Meter output channels)
For doing active crossover, I decided each stereo channel (pair), instead of being left/right, or now high/low...
Left channel is low-pass and right is high-pass.
For a three way setup, you could add another channel, just strictly mid-bandpass, and run it as a left/right setup and pass it to the amp...
And that's all I did...I have two Xonar sound cards...one handles drivers side (front/rear) and the other, the passenger. These output to a pair of 4-channel TRU amps...again, one for passenger side, the other for the drivers side...
Here is the amp.
4 X 1/8" stereo jacks (handmade) into 8 chassis-mount RCA's, and then interconnect RCA's into the amps (also handmade)
The dual Xonar cards!
The VU meter out is line level only, and the sub out goes to a 2 channel Alpine under the drivers seat...
Also note, the LS filter is 3-way + sub, but it also has full-pass output on the first two channels (for the VU meters)...very nice filter!
I could of done this with 1 soundcard (8 channels), but without sub or VU meter output. I could of spliced in for both, and let the amp do
the sub crossover, but this gives me more flexibility and control...and the possibility of maybe 3-way in the future!
Also, I use Virtual Audio Cable as my default playback device (in Centrafuse)...this is picked up as the audio input with Audiomulch...AM does it's thing, then outputs
the the actual jacks on the soundcards...
This was ONLY possible with ASIO4All drivers (else not all 16 channels were visible) and ONLY with 1731 Vista drivers (running on XP no less), or else there was 'cross-talk' between the channels, and/or the sub/center output jack wouldn't output discreetly.
Did a LOT of testing (drivers, operating systems, etc) and hair-pulling to make this work, let me tell ya!!