Speaker wire polarity on a powered subwoofer

My Cary SLP 50 B preamp is inverting so I reverse the polarity on my speaker cable. If I run rca line level out from my preamp to the sub I obviously can't access the internal wiring on my powered sub to reverse the polarity. Does it really matter on a sub? What do I do?
the biggest polarity problem on far to many recordings is bass, which oftentimes is out (opposite) from the rest of the music. IF your preamp or dac remote has a Polarity button (typically misnamed Phase) then you can bring both in line with the push of a button, otherwise...
since the audio for each instrument is recorded separately, how on earth is it out of polarity with the rest of the music? Thats really not how polarity works.