Cost: $100 to - $$$

Difficulty:

Time: 2 to 10 hours

The 10 speakers stereo system of the Bmw E34 E32 gives a ok sound to the majority of us... But because we are Bmw owners, "OK sound" need to be upgraded.

Installation of a Pioner disc changer. Thanks to Gordon.

Stereo system

The stock system consists of a tape deck, CD Changer (optional), amplifier/crossover (a four channel amp, and it is ~20 watts/channel, amplifying ~5 WPC that the head-unit produces. The 10 channels mentioned so frequently are actually just the speaker-level outputs of the passive crossovers (which are inside the factory amp box, arguably not a very good place for them). BMW calling it 10-channel is an example of "peak marketing." ) located behind the carpet on the left corner of the trunk, and 10 speakers:
• Two 5.25" midbass in the front kick panels.
• Two 3/4" tweeters in the door pillars and two 2.5" midrange in the dash.
• Two 5.25" midbass and two 3/4" tweeters in the rear shelf.

If you are not happy with the sound, there is some options: ADS Stereo upgrade PDF FILE
I want more base:
• Adding a subwoofer only.

I want a cleaner sound and I don't want to touch the amp:
• Changing the speakers only (not much improvement).
• Changing the radio only (not much improvement).

I want a cleaner sound and more power:
• Changing the amplifier / crossover. Soon

I want a killer sound and want to change everything:
• All the above + new radio installation. Soon

Whatever you do, the wiring of the E34 stereo is strong enough to take the power, no need to change it, but if you change the whole system, you will have to run an RCA cable.

The problem with the BMW OEM stereo is that the crossovers are located INSIDE the amp (which is mounted in the driver's side rear quarter panel behind the trunk carpet). There is no way to get a full range signal from the amp. The preamp signal from the head unit goes into the amp and then 10 crossed over signals come out of the amp for the speakers.

All newer BMWs have the in-glass electronic systems by Fuba. The following information applies to these cars as follows: E31 - E32 - E34 - E36 and up

These cars have 2 or 3 antennas in the rear glass, including one which is the defroster wires, all embedded or printed on the inside of the glass. The usual configuration is a small computer/antenna selector/signal amplifier in the left side C-pillar. This small box can be accessed by removing rear seats completely then removing large plastic trim panel.

The "box" gets a signal from the radio via a thin (aprox 1/8") coaxial cable. This is an IF (Intermediate Frequency) signal out of the radio. My best guess is that it comes as a variable voltage level not a data signal. The computer uses this information from the radio to learn how strong the reception is at a given instant. As usual for a computer, antenna or antennas are selected at maybe 30 or 60 times per second. It is possible for the computer to select 1 single antenna or combine 2 and maybe 3.

If the original BMW radio is replaced with an aftermarket radio, the computer defaults to one antenna, probably the largest array. The reception quality will become fairly poor using a single antenna in the rear glass. The best solution apart from re-installing the original radio is to install a single antenna in the rear fender, the old fashioned, old reliable way. Otherwise an aftermarket radio with 2 antenna inputs (diversity system) would be a near remedy: In this case use the default antenna in the rear glass plus an aftermarket small electronic antenna inside the front glass.
BMWE34.net: I don't agree with that. I have never heard of this problem on the E34.

Note: No reception on the AM band means the power is somehow disconnected from the antenna box in the C-pillar. Check for voltage at the box itself. Many times when installing an aftermarket radio the power lead to the antenna box is left disconnected. It should go to the power-antenna lead, (blue or green) of the aftermarket radio.

Thanks Tim T.& Peter W.