I have an amp hooked up to a single sub. Today I noticed that my sub increases bass and decreases bass as I change the EQ settings from the HU. The settings for my sub output don't change. Shouldn't my EQ settings only adjust the bass for my interior speakers? I still have the stock speakers.

I also noticed the my RCA output is not as good as my old HU. I had a Pioneer flip screen (forgot the model) and don't remember my subs' volume increasing as I adjusted the EQ on the HU. My RCA output was also good. My sub used to hit harder. Could there be something wrong with my HU?

Thanks for your input

I have never tested to see if the EQ effects my sub, but there are 3 sets of RCA outputs to drive amps. Front, Rear, and Subwoofer (non fading). Try fading front to rear to front and see if your sub changes. If so, you may have the wrong RCA output driving the sub amp.

Believe me, I made sure my RCA output is the one labeled subwoofer

the eq will affect the sub woofer freq's if you adjust the sliders/freq's that correspond to the sub's outputs. Where ever it is that you have the low pass crossed at, i.e. 80hz, then any eq slider that affects 80hz and below will affect the sub's output. the other eq sliders/freq's, (80hz on up) will afftct the cabin speakers. It all depends on where you cross your freq's at that will determine which freq's/sliders will affect which speakers. hope i made sense with that...