Originally Posted by maxcichon

It's a combination of poor engineering/setup and the OEM (Infinity) headunit really not being very good.
A simple and cheap fix is to install the capacitors as this thread mentions. I have replaced my head unit with a Pioneer ($150) and really love it. I also ended up replacing the door speakers with Infinity Reference for ~ $50.

All of these things make a big difference. Start small. Stop when you are happy!

If you need capacitors, I will send a pair to you for $6 ready for install.