How do you add a little more thump? I think the system is fairly well balanced but I'd switch out the factory sub and add an 8inch JL audio sub if I could. But I cannot find any information about the bose system (it's like it's the blueprint for fort knox).

Does anyone know how to do this?

 

I have an 08 S4 and find that I'd like more bass too. Bose doesn't publish specs but a few 3rd party folk have and find no deep bass and no very high frequencies. They do sound pleasant and have a cool volume vs speed/ambient soundleveladjustment now. Boseequalizes the output frequency response oftheir amplifiers to fill in holes/peaks in their speakers and surroundings. So you cannot substitute other speakers that expect to get a flat frequency response input. I think owners either replace the whole Bose system or turn up the bass control.

 

Not sure if this will help or not but here it is:

http://a4mods.com/index.php?page=web...es/stereo.html

this is a pretty good write up of how to tap into the factory system (Bose Symphony II)