All right, all four outputs of the DSP work. I hooked up the two fronts to the Emotiva first, and they worked, and then I hooked up the two rears, and the both worked. So it really does seem to be the ADA1000-4 that's the issue, which surprises me. I'm sure it was tested plenty before being shipped, so I have to wonder why I'm not able to get any sound out of it.