E34 Stereo Upgrade

Here’s a quick write up on the stereo upgrade I did with my E34.

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Removing Old Speakers
The original speakers were 5.25inch Pioneer coaxial units. Over time the diaphrams on all four had severly perished so they produced little or no sound. I sourced new Pioneer units to directly replace them.


My E34 also has speaker mounting points in the top of the dash on both sides. Wiring for these additional speakers was also present. This would allow using composite speakers with the mid/low speaker in the footwell and a small tweeter in the top of the dash. Is this standard on all E34s? I’ve read good reviews on Rainbow Audio composite speakers like EL-C5.2 which would fit. There is plenty of space behind the footwell speakers to house the crossovers that composite speakers would require. I may do this sometime down the line. I think additional amplifiers might be necessary with this setup to get the most out of it though.

Renovating Speaker Covers
The rear hat shelf speaker covers are backed with a black foam. Over time the sunlight had caused this foam to degenerate to the point where it would turn to dust if touched. I used 3mm open cell foam that is used for making filters for PC fans to replace the perished foam on the covers.

Installing Subwoofer Wiring
The subwoofer requires a remote wire from the head unit (usually labelled ANT) and a R and L RCA cable. The remote wire triggers the sub to power up when the head unit does. Power for the sub is taken directly from the battery. An inline fuse is supplied with the cables for the sub. The battery in my car is under the rear seat so the supplied power cables were long enough.
I wired the remote wire and RCA cable from the head unit out of the passenger side of the centre console and along the left side of the cabin. From there it passes under the rear seat and out through the bung in the rear fire wall to the boot.
Note that there is a remote cable available under the rear seat from the factory loom, I decided to wire in a new one as I wanted to use a heavier gauge wire and didn’t want to modifty the factory loom in any way.
I also used a 4.5m RCA cable which was just long enough. If I were to do this again I’d use a 6m cable instead.

I wrapped the new wiring in Tesa tape to look like factory installed loom.

Subwoofer Install
I mounted the subwoofer on the underside of the hat shelf. There were already 8mm mounting points available so I cut some threaded bar to fit. The mounting itself is made of 6mm plywood wrapped in anthracite felt covering.

Stereo Install
Stereo has a short body as there are no mechanicals onboard. It has standard ISO connectors on the back so I used a BMW 17-pin to ISO converter. I added the new remote wire to this adaptor so I didn’t have to modify any of the original loom. The short stereo would allow for a small amp to be fitted behind it if required also.
The head unit has a DAB receiver and comes with an antenna supplied. I chose not to install this antenna due to the shortage of DAB stations in Ireland however.

Stereo Hacks
The head unit has both a front and a rear USB input. I like the look of the stereo with the cassette door closed so decided to make a device to allow the rear USB input to be used without having to take the stereo out.
I stripped down a broken cigarette lighter USB charger and soldered on a standard USB male connector. I wired this up from the ashtray to the back of the stereo. Now instead of the usual lighter behind the ashtray panel I have a USB port that connects to the stereo. There is enough room for me to have a small USB key connected with the ashtray closed that I play music from when not using Bluetooth etc.

Wow, that’s some tidy upgrade! Nice to be able to enjoy spotify with a period unit. Much attention to detail :wink:

I’m looking at a speaker upgrade too for the merc - the sound is a bit tired with the new head unit