Quoted from msj2222:Is there any advantage to using the rca input rather than speaker input?
If you are connecting to the terminals on the cabinet woofer, my guess is that it's preferable to use the speaker level inputs (spring clips) on the sub, not the line level inputs (RCA connectors). That's how I have all mine hooked up. I'm hardly an expert in this area, but I would think you would only want to use the line level inputs on the sub if you are tapping into the signal before the amp.