I just got a hand me down MTX 12" sub to use til I get my Epik Caliber. I go to connect it and the bugger doesn't have a sub in? It has two sets of reg speaker wire type connections and two sets of RCA. It also has the crossover gauge and volume control. It is powered. I tried connecting it to my amp in various speaker sppots to no avail.
Help?

The RCA jacks are the subwoofer inputs.

The RCA connectors are probably labeled Line In/Out or Low Level In/Out. Connect your sub out from the AVR to either the left or right RCA in.

my old sub had a right and left RCA. i used a splitter to connect my lfe out on my receiver to both of them.