Bass from left side only.

[Kylegypo]

Hi.
To put it simply I have 4 speakers and a sub in my Megane II 1.9dci dynamique. When I balance the audio to the right hand side of the car (for test purposes) I get zero bass. Even the sub stops outputting sound completely. My headunit is an Alpine iDA-X303 with a KTP-445A (In line amplifier). Could this be a polarity issue? But if so why no sub?

I appreciate your help.
Kyle

[roganp]

What's powering the sub? presume there's a separate amp for that. My guess is the sub amp is hooked up to the left subout RCA only. Look for a setting in your headunit for mono sub output or run a pair of RCA and sum the signal at the amp.
Why there's no midbass is a different story. Won't be polarity cos cancellation only occurs when both sides are playing