Hi Hoping there's someone out there who can help on this. I've just fitted a Pioneer DEH-P65BT in my B6 A4 I think not bose (see previous post http://www.audi-sport.net/vb/showthread.php?t=52539 ). However, whilst the front speakers work ok, there is nothing coming from the rears and only the tiniest bit of bass coming from the sub. I know the standard sub is meant to be a bit of a pussy but this is SO quiet you really have to concentrate to hear anything. I know from reading other threads and advice from AndyMac that the amp needs to be powered so I've connected the power lead to the power antenna lead and am using the autoleads adapter PC9-404 which connects the amp plug to the HU via the pre-out sockets. I've no idea why this is happening - I thought the rears and sub should work (albeit less powerful than the fronts). Don't know whether it's relevant but the new HU apparently can run a sub directly (it's called direct sub drive apparently) so could it be that the amp isn't switching on but the feeble output from the sub is due to the HU? I'm planning on wiring the rears directly eventually but for now would like to hear something from them and at least as much bass from the sub as I had with the original HU. By the way, I have played with the sub controls on the HU and put all levels up to max but hardly makes any difference. Any help anyone can offer appreciated.