I finally got a real chance to test the audio system in the i35 I bought. I am fairly happy, but noticed the passenger side sounded louder and more crisp. So I proceeded to fade and balance the audio.

When faded front right it was great. Faded back right it sounded good.

Front left and back left are noticeably lower in volume and slight distorted.

I will be replacing the head unit soon with an App Radio 3 and using the PAC ROEM-NIS2 to interface with the Bose system. If the system all worked, I would be happy enough with the sound. With one side being a little off, I am trying to see if I can fix it or if I just need to bite the bullet and install all new speakers, amp, and sub. I am actually quite alright with the boses sub. Can I retain it and use it with a new sub? I think I read they ran off 1 ohm which makes it difficult to use outside the standard bose setup.

Any idea what could be the issue? Should I bother to fix or just replace?

Thanks for your help!

Here is a video of the problem:

[youtube] https://www.youtube.com/watch?v=x5jctRaiNME [/youtube]

Ended up being the head unit. I replaced it with an AppRadio 3 and it fixed the issue.