Stereo - Subwoofer


Cost: $100 to $500


Time: 2 hours

Procedure courtesy of Derek I. and photos of Anthony and his M5

To install a subwoofer, you can change the complete stereo system and add an amplifier and a crossover or you can use the stock crossover on your Bmw E34/E32.

Basically you don't want to touch anything in the stereo system, meaning you tap the signals from the radio's wires located at the amplifier/crossover and add another amp.



1. Locate the carpeting on the left of the truck. If you are lucky and have an M5, you have an optional storage compartment
2. Remove the 1/4 turn screw (other than M5) and remove the side carpeting.
2. Remove the bottom carpeting too, locate the amplifier/crossover and remove the 4 phillips screws.
3. Now you have two choices, you can tap the wires or if you want the best sound, you can remove the wires make a nice split.

Left Pic: Detail of connector with strain relief detached.
Right Pic: Detail of other side of connector.

4. You have to tap on the signals from the radio at the amp: (Wire colors depends on Bmw year)

Rear Left (+): Yell/Blue (Yellow Black)
Rear Left (-): Yellow/Grey (Grey or Brn/Orange)
Remote power for new amp: White
Rear Right (+): Blue/Violet (Blue/Black)
Rear Right (-): Blue/Grey (Blue or Brn/Orange)
5. You might need to strip some of the factory harness tape to allow enough play in the factory wiring to attach the big wire taps (or the splice).

6. You can use a short piece (around 8") of Left/Right RCA wire (RCA cable with individually insulated +/- wires as opposed to an RCA with the ground shield woven around the outside of the + wire) for the pre-outs of the new amp. You just have to use another male/male RCA extension to connect your cable to the new amp. (Thanks Derek for the pictures)
7. Find a location for the amp, either at the back of the rear seat (in the trunk) or like Anthony, relocate the stock amp and the new one at the same location.
8. 12V to power the new amplifier (big gauge wires) should be taken directly from the battery with a inline fuse as close to the battery as you can. For the ground, don't try the rear tail light bolts... This is a lousy ground and will give you a lot of alternator noise (how do I know? Don't ask). One of the rear seatbelt bolts will be perfect.
9. Now you just have to connect your subwoofer(s) to the amp. If you use one sub only, make sure you have a bridgeable amp.

You can place the subwoofer where the ski bag used to be, and if you don't have a ski bag, you can pop out the metal plate that covers the opening and put some rubber tubing around the edge (to keep from getting things caught, cut, or ripped). Then push the box right up to the opening. The armrest really needs to be down in order to get the bass response.
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