Just installed the active sub but not sure if it's working correctly. As it's my first, don't know what to expect. My Sony amp has a singe RCA out for the sub, the sub has twin RCA in (for DVD) and terminals for L & R (for the amp). I'm connecting to the terminals. I've cut down a single to twin RCA to suit, connected single RCA to the amp, the shield on both leads to the - terminals (L&R) and center on both leads to the + terminals (L&R). Is this correct? Assuming above is OK now doing setup for the sub on the amp. On the amp set sub to on, start the tone test to adjust volume on all speakers, but the volume is way down on the sub, not even close to the others. It's also more like a deep "hiss" than a clean tone. Should the sub give equal volume, or is this normal? Any assistance appreciated.