Adding a subwoofer..need help

[jdog0411]

This weekend's project is going to be adding a subwoofer to my stock 2004 325ci. I have the base stereo.

I am building a box to go in the trunk, and will be utilizing an Infinit Kappa Perfect 12" sub, rated at 350 watts RMS in a sealed enclosure. I installed my previous system in my Explorer, but that was much more straight forward than this appears to be in the BMW. I know there is a factory amp powering all of the various speakers throughout the car. I am going to eventually be replacing the factory headunit and upgrading to component speakers, but I'd like to get the sub added to the stock system since I can get that completed before doing the other things.

What do I need to do to get the sub working with the current system? Do I need to bypass the factory amp (where is it), use speaker level inputs into the amp, etc? It doesnt' seem like it would be that difficult but I would appreciate any tips from anyone who has done this. I'm not an expert in car audio installation by any means.

Thanks!

[jdog0411]

bump

[Golden1]

If you are maintaining the OEM headunit, then you'd have to tap into the OEM wiring that goes to your amp. I tapped into the wiring for the rear speakers to give my subwoofer sound. No need to bypass the OEM amp, just tap into the rear speaker wiring before it reaches the OEM amp.

[jdog0411]

so I would tap into the wiring, and run the wires to my aftermarket sub amp, and then on to the sub? What is the best method for tapping into those wires in order to get a sturdy connection? Where is the factory amp?

Sorry for all the questions, I am just learning about the car. I am also searching the forum in the meantime...thanks in advance.

[Ken@BSW]

To gain a signal that your amplifier can use, the best method is to tap into the speaker wires on the input side of the amp, coming from the factory head unit. You will need a line-output converter, such as the one I will link below, to convert your factory balanced input to a usable RCA cable. Other than that, installing the system should be as straight-forward as it was in your explorer.

http://www.bavariansoundwerks.com/product.php/II=480/_cid=285

[BLAU III]

ive never used a line in, will it function the same way with the amp as normal rca's coming from the reciever. like will the amp automatically shut off when the car does. also is it safe to wire the amp directly to the battery in the truck.

[jdog0411]

Thanks for the info...I'll give that a shot. The more I think about it, the more I'm thinking of just replacing everything, from the head unit on down to the speakers. But this would be a good intermediate solution to get some extra bass relatively easily.

[jdog0411]

From searching the forum, I now know where the factory amp is located. I posted another thread with questions on exactly how I get to it. Doesn't seem like BMW used simple fastners for anything on this car.

[birdsley14]

I don't see any problem connecting to the battery in the trunk, I would just use an in-line fuse to protect your amp. my issue has been finding the amp. I haven't taken the carpeting out of the trunk, but I thought it was on the left side of the trunk. Mine has a small storage compartment there. Not sure?
Also, my sticking point is getting from the factory speaker wire to RCA for the input on my amp. I'm assuming that's what this line-output converter does? After that this should be pretty easy whether I go from the factory speakers or the factory amp, we're just talking about signal quality. I'm just looking for a little boost by adding some subs I had laying around. This should also help save some wear and tear on my factory speakers.

[Halston@BSW]

From searching the forum, I now know where the factory amp is located. I posted another thread with questions on exactly how I get to it. Doesn't seem like BMW used simple fastners for anything on this car.

For those of you looking for the amplifier. Or how to correctly install the LOC(line out convertor) and how to do the remote turn on.

Please just shoot me a PM with your email address and I will get you the proper installation instructions. They will be for our products but you can modify them slightly for your personal use :)

Make sure your spam filter allows emails with pdf files.