Audiophiles: Subwoofer help

[Maengelito]

Check the crossover settings, also check that you didn't reverse the polarity of the wires between the amp and speaker.

reversed polarity still delivers power, but backwards. he wouldn't notice low volume from that error, it'd just be the inverse frequency. in my experience, that still makes a lot of noise

i've hooked up the polarity backwards before on my sub. it sounds like its cancelling out any bass put out by the regular speakers. it could be that the polarity is wrong, but thats an easy check. it sounds like its the head unit though