@erik_squires I did not mean a microphone, I mean to just test the XOs with just a signal and probably some power resistors where the speakers go.
Your idea of the DATS does the speakers, so it is conceptually the same type of thing, just I am aiming it the other way to look solely at the XOs.
Either way we are both splitting the system down the center to figure whether (in your case) the back half is working (speakers), and in my case, whether the XOs are NOT working.
Our approaches are matched (like a Darlington pair).