Questions about 2008 135i base audio...

[e32lover]

Gday, I have had a browse through the forums, but couldnt find the exact answers I need.

I have a 2008 135i with the base audio (4x4 inch speakers, and possibly the underseat subs. No tweeters or amp)

I have read here that the signal is heavily eq'd by the factory head unit. Is this still the case if the headunit is reprogrammed to put out balanced differential line level ouput (as would be the case when it is paired with the logic 7 or hk)?


Also, I understand that the underseat subs and the front mids are run off the front 2 channels of the headunit and the rears off the rear channel.

I assume that the front channel is not crossed over in the headunit as it must feed both a low and high range speaker is this correct?


I was thinking about pinching the signal from the kick panels, from the front mid input. If I have the headunit reprogrammed, this should be a clean, non crossed over full range signal yes? If this is the case, then Ill use that, and install the crossover for my splits in the door itself to avoid having to run new wires through the door.


Finally, I was wondering if it is possible through coding to assign the front hu outputs to output a line level ballanced signal, and to keep the rears ouputing a speaker level signal so I do not have to change the rears as well.


Any advice would be greatly appreciated. I am looking forward to learning lots on this forum

Thanks.