Hey guys, I'm hoping someone can give me some help or even point me in the right direction as I'm just about tearing my hair out with this. My old Symphony II head unit went haywire a month ago so I looked into getting a replacement HU and found some nice looking aftermarket ones from Xtrons, so I managed to get one for a bit of a steal from Ebay and duly set about plumbing it into my B7 A4. It works absolutely fine and is actually pretty good, but I'm getting absolutely no sound at all from the rear speakers. After a copious amount of time Googling things, I have figured out that this is a well-trodden subject but I just can't seem to find a straight answer. So far, I've figured out that my car is evidently not equipped with the Bose system, so I must have that amplifier for the rear speakers and the sub on the rear parcel shelf somewhere at the back. The only thing I can find from Xtrons is this page, which is not very helpful as I've never tinkered with a HU harness or OEM wiring looms before and fear that I'd mess things up. I evidently don't have the blue 'amp-cont' wire (which I assume is found in Bose-equipped cars) and have read several different potential solutions to this issue, some requiring 'Hi-Lo converters' and stuff and others saying that I need an ignition feed and stuff. Can anyone help?!