The Crown XLS series have compression, crossover and other settings, but not for the input. They also have a Phoenix connector on the rear for contact closure, but from what their tech support could tell me, it only shuts off the display and the bestest, most coolest thing about it- THEY DON'T INCLUDE THE STUPID PART FOR MAKING THIS HAPPEN!

I called and explained why that's insane and they sent one to me, but I was already back from that three hour one-way trip and nobody up there has anything like it, or would know what to do if they did.

Check the levels going into the line level adapter and on the amp (if it has that). Beyond that, you're going to need a lot more power if they want it to be really loud, as well as different speakers if the ones that are in place don't have a back-box of some kind, assuming they don't want a lot of sound transmitted to the space above that room (unless it's attic space). If the space above is attic or not, as long as it has room, think about installing small-ish boxed speakers and make a custom grill. That way, an amp with auto turn-on, DSP and enough power will give the results you want. I would look at speakers that can go down to about 60Hz- that way, you won't have to worry as much about size but make sure they can handle the power.

Look at QSC amps- they're generally bulletproof.