MDroz

I posted this in the A4 section, but since it’s all the same equipment as the S4 I thought I’d post here too just in case.

I'm having an issue with my 2001 Audi A4 with the BOSE system. From 2 years ago up until this fall I've had no issues with my sound system (original headunit and Kenwood ddx396) but recently something happened and now the bass / rear deck speakers have low volume. All speakers are working, there is just a lack of low bass frequency throughout.

I've messed with all the faders, balances, and x-over, and I'm not sure what the issue is. Something I will note is that there used to be the pop sound from the amp turning on and off and now I do not get that. It's almost as if the amp isn't being fully powered or isn't turning on.


Here's what I've replaced:
Rear deck speakers
Headunit (upgraded to New Kenwood DMX958XR)
2 different OEM BOSE amps (A4/S4 80W, & A8/S8 200W)
I've gone through 4-5 wiring harnesses: cheap eBay Chinese harnesses, Metra 17-1787, etc.