AUtomatic HPF on Head Unit?
 

Recently the ground wire on my sub was a little loose, and when it would cut out, I noticed that the lower frequencies were filtered out of my component speakers. My component speakers are powered by the head unit, and there is no setting to turn the HPF on or off, or adjust what frequencies it filters. The head unit I'm using is a JVC KD-R540, and my component speakers are Alpine SPS-610s. Is there any way to disable the HPF on this head unit, or is my sub my only source of bass?

Your deck doesn't have any form of high-pass filter on the speaker outputs. Your speakers just don't produce any bass.

Oh. I feel stupid for not checking the frequency response now haha. I thought the little woofer cones would go a bit lower than 70Hz.

meh - the rated frequency response doesn't really mean all that much. It takes a fair bit of effort, and the right speaker, to get mid size speakers to make decent bass.