my old receiver gave up the ghost, and I went out and bought a new Pioneer VSX-521 one
it's a pretty basic unit (i'm not an audiophile) but had everything I needed. multiple HDMI in, supported the audio formats I had, etc
the issue I've run into is that the old sub just had the 2 stripped wires you clamp down. The new receiver is looking for an RCA style plug
do I need a powered sub? or can I just solder on a RCA plug onto old wires(and if so, does polarity matter?)