installing subs/amp in trunk

[dudley821]

I am installing 2 12" subs and an amp in the trunk of my '01 330Ci. Can someone tell me everything I will need to do to install them? Specifically, how to wire the subs and amp into my car stereo system. It's stock, not H/K btw. Thanks a lot.

[CWolfey]

It is actually pretty easy to do this in a BMW, you can get all the wires and connections you need in the trunk. You will tap into the hi-level speaker leads and either connect directly to the amps hi-level in or use a line output convert to convert that signal to RCA jacks. And the battery is in the trunk so connecting the power and ground should be no problem either, for remote lead you will use the White wire on the amp.

Good luck.

[dudley821]

Thanks a lot CWolfey, that's exactly what I needed.

[nothing235]

My 2001 330Ci has the HK upgrade. I want to add a sub/amp in the trunk, but I'm not really sure how to get the signal without creating noise in the whole system. I've read tht its very easy to create a lot of noise because it is a 'Closed System'.
This device looks like it would do the job:
http://www.mileageman.com/pages/AddAmp.htm
However, it seems very pricey for what is. I think I'd be paying mostly for the instructions.
Does anyboy have wiring schematics for the subs in the trunk so I could build and install the device myself?
Thanks.

[dudley821]

Can someone explain what CWolfey said in more detail? Like where exactly the hi-level speaker leads are and such. Thanks.

[CWolfey]

The speaker leads are at the amp in the trunk.
http://www.bimmerfest.com/forums/attachment.php?attachmentid=25109

[Kaz]

My 2001 330Ci has the HK upgrade. I want to add a sub/amp in the trunk, but I'm not really sure how to get the signal without creating noise in the whole system. I've read tht its very easy to create a lot of noise because it is a 'Closed System'.
This device looks like it would do the job:
http://www.mileageman.com/pages/AddAmp.htm
However, it seems very pricey for what is. I think I'd be paying mostly for the instructions.
Does anyboy have wiring schematics for the subs in the trunk so I could build and install the device myself?
Thanks.

I'm willing to bet that this device taps into the audio signal going into the HK sub, level converts it, and presents 2 RCA outs. That would be pins 1 (+) and 6 (-) on the sub amp side or 6 and 14 coming out of the main amp (the sub amp runs off the main amp).

[nothing235]

I decided to do a little research online and with an oscope before I started wiring.

The easiest/best way to get signal for the aftermarket amp/sub seemed to be splicing the outputs from the crossover/amp? (the black box next to/feeding the rear stock subs) and use these as high level inputs to the aftermarket amp.

To prevent noise I used the shortest possible power and ground cable directly to the battery. I also made sure that no signal wires were crossing ground wires.

Finding a remote wire was another chore. At first I thought I could use the pre-wired cd changer remote wire, but I found out that it was not 'activated'. So I used the remote wire attached to the factory amp in the trunk. It is located behind the carpet on the driver side of the trunk. It's one of the white wires if anybody is looking.

Anyway the end result is great, its very loud and clean. No detectable noise. The only problem is that even with all the gains turned down (Including the 'bass' setting on the factory head unit) the sub is still pretty loud. To compensate for the I'll probably have to add some pots to the high-level signal wires in the trunk.
Thanks for your help guys!
If you have any questions let me know!
Nothing235@hotmail.com