Originally Posted by walc

I just replaced the oem head unit, with a PANASONIC CQC7105U In-Dash Player & Sirius Tuner, and I noticed the same thing.
The in-door speakers are booming, and vibrating my left leg, and I don't feel anything from the back speakers.
I set the new head unit sub woofer setting at +2, whatever that means.
I don't know what the High Pass Filter does either.