Audio Systems: subwoofer music, vocal ranges, lowpass filter

Question
is there suppose to be music coming out of my subwoofer or just bass

Answer
subwoofers really should be whats called "lowpassed" which ultimately means only the low frequencies, or bass, comes out.  if you hear "music" or like vocal ranges of music etc. coming out of your sub then you don't have the lowpass filter on, which isn't good.

to sum this up,  for your sub to sound right, it should only be making bass.