2004 M3 - Harman Kardon Question

[K-rock]

Just picked up a 2004 M3 Coupe...
I got the Harman Kardon option, not as sweet as I expected (by the way it still has the subwoofer button).
Need some suggestions on possibly adding an amp, or powered subwoofer without voiding the warranty. From the info I've gather thus far this may not be possible. It's like the system is on the verge of hitting hard, like a Bose, but just doesn't get there.
Any suggestions?
Plus, will Harman Kardon send me data sheets on the system showing a wiring diagram, power requirements, load capacity...blah blah blah, basically the specification documents.

 

[vlad]

Uh, if I'm not mistaken, that's not a sub woofer button. It's more like a spatial imaging selection, although it does pump the woofer up a little. But check yours, turn the stereo on fairly loud, turn that button off, climb into the rear seat and check to see if the sub is still working. Maybe BMW changed something.

I have not found any good upgrades that don't require splicing into the wiring harness, and I'm pretty sure that would void a warranty.

As for Harman sending you specs, give it a try, but I'll bet that they refer you to BMW.

 

[Tom]

Hello K-Rock, congrats and welcome.

There are a few routes you can take.

1. You can get an RCA line convertor and tap it into your current rear speakers. This way you can run your own amp and speaker setup.

-Or you can get these pre-powered items.

Infinity Bass-link

JBL Basspro

Like Vlad said, since you are tampering with the stock setup, all of these mods will void your warranty in the event of an electrical problem.