**PLEASE NOTE THIS IS A WORK IN PROGRESS AND WILL BE UPDATED REGULARLY**
Summary:
Remove the DSP amp, add a couple of cables, and your formerly DSP stereo will revert to 5V balanced outputs on all 4 channels which can then be amplified. No Cleansweep needed.
see MTX504 on Stock Bracket.jpg
It has been documented in previous posts that you can get an analog output from the radio unit by disconnecting your DSP amplifier from the system but with 2 issues: no rear channel outputs and loss of the CD changer input (see DSP Explained below).
see Stock Harness - Zoom.jpg
The other issue is how to get 4 channels of analog output from a radio that only provides 2 channels of digital. As mentioned, the radio automatically switches from digital to analog output when you remove the DSP amplifier and disconnect power to the head unit temporarily. Let me repeat that to be clear – removing the DSP amplifier will still leave a constant volume signal, you also need to remove power from the head unit temporarily (I disconnected the battery).
Unfortunately, the stock wiring harness only contains wires for the front channels since the DSP amplifier splits it into 4 channels itself (see previous photo, bottom left corner). Lucky for us, while DSP was standard on M5's in the US, it was not standard on all BMWs and the radio is common. Metra, an aftermarket wiring harness company, makes a replacement harness for the radio that contains 4 channels of output. And presto, just by ordering a Metra 71-9003 wiring harness ($10 inc. s/h on eBay). BTW – the radio changed in 2002. If you have a 2001 or lower you need 70-8591 inc rca plugs or 70-8590 with just wires.
The BMW and Metra radio harnesses are actually 4 small harnesses in 1 harness carrier. Pry the tabs on the side of the speaker wire harness gently and it will slide right out of the larger Metra carrier (do this one first in case you break the carrier!). Remove the old speaker wire harness from your stock carrier, tuck the old wires out of the way and insert the new harness!
see Stock Harness w RCA.jpg
So now I have a stock radio with analog outputs. What I didn't realize was that the outputs are not low level (typically in the 100mV-1V range) but rather are balanced outputs with a peak of 5V riding on a 0.8V baseline (per el_duderino and TJJ at X5Board: http://www.x5world.com/bsws-mobile-e...ght=DSP+output). Luckily Scott at MTX was very helpful -- ALL of their amps can accept a balanced input via RCA cables.
(rated at 8A each) from Radio Shack. They will allow me to remove the equipment from the vehicle without having to unscrew any wires.
see Speaker Wires 001.jpg
Next step was to modify the brackets. As mentioned I wanted to mount the amplifier in the stock location. Finding the right size amp was ok, but getting one with mounting holes that match wasn't going to happen so I took a thin strip of sheet metal and bent it to make an extension.
see Amp Bracket 003.jpg
In addition, I needed to mount the passive crossovers so I took some additional sheetmetal, bent a couple of mounting tabs onto it and then mounted it to the bracket between the amplifier and the cd changer.
see Crossover Bracket 001.jpg
Now we have the whole story sorted out:
Hope this helps everyone and sorry to those who were misled by stereo shops who didn’t know better!
Doug
Gustav and M5Board.Com, X5Board.Com & BSW: For hosting and sponsoring so much information it took me 2 months to read and digest it all!
Bob Hazelwood: For providing 95% of the information including full wiring harness details and suggesting this was even possible!
BMWMPWR: For confirming the CD Changer to Radio part number
el_duderino & TJJ (from X5Board): For the X5 analog output information
Dave_GT: For pictures of his non-DSP Eu stereo for comparison
Scott Abel @ MTX: For advice on amplifiers, subwoofers, speakers
The screen in the front of the car is simply a dumb terminal that passes commands to the 4 units in the back: radio receiver, navigation, cd changer, and amplifier. In a DSP vehicle, the nav unit is connected to the radio (analog), the radio to the DSP amp (digital), and the CD to either the DSP amp (digital) or the radio (analog). The output from the radio unit is 2 channel (front) only and does not vary with volume. All modifications to the sound (volume, fader, treble, bass, DSP equalizer, etc) are controller by the amplifier which then provides 10-12 channels of amplification (depending on M-Audio or not).
Summary:
Remove the DSP amp, add a couple of cables, and your formerly DSP stereo will revert to 5V balanced outputs on all 4 channels which can then be amplified. No Cleansweep needed.
see MTX504 on Stock Bracket
It has been documented in previous posts that you can get an analog output from the radio unit by disconnecting your DSP amplifier from the system but with 2 issues: no rear channel outputs and loss of the CD changer input (see DSP Explained below).
Unfortunately, the stock wiring harness only contains wires for the front channels since the DSP amplifier splits it into 4 channels itself (see previous photo, bottom left corner). Lucky for us, while DSP was standard on M5's in the US, it was not standard on all BMWs and the radio is common. Metra, an aftermarket wiring harness company, makes a replacement harness for the radio that contains 4 channels of output. And presto, just by ordering a Metra 71-9003 wiring harness ($10 inc. s/h on eBay). BTW – the radio changed in 2002. If you have a 2001 or lower you need 70-8591 inc rca plugs or 70-8590 with just wires.
The BMW and Metra radio harnesses are actually 4 small harnesses in 1 harness carrier. Pry the tabs on the side of the speaker wire harness gently and it will slide right out of the larger Metra carrier (do this one first in case you break the carrier!). Remove the old speaker wire harness from your stock carrier, tuck the old wires out of the way and insert the new harness!
So now I have a stock radio with analog outputs. What I didn't realize was that the outputs are not low level (typically in the 100mV-1V range) but rather are balanced outputs with a peak of 5V riding on a 0.8V baseline (per el_duderino and TJJ at X5Board: http://www.x5world.com/bsws-mobile-e...ght=DSP+output). Luckily Scott at MTX was very helpful -- ALL of their amps can accept a balanced input via RCA cables.
see Speaker Wires 001.jpg
Next step was to modify the brackets. As mentioned I wanted to mount the amplifier in the stock location. Finding the right size amp was ok, but getting one with mounting holes that match wasn't going to happen so I took a thin strip of sheet metal and bent it to make an extension.
see Amp Bracket 003.jpg
In addition, I needed to mount the passive crossovers so I took some additional sheetmetal, bent a couple of mounting tabs onto it and then mounted it to the bracket between the amplifier and the cd changer.
see Crossover Bracket 001.jpg
- Disconnect your battery
- Remove the stock DSP amplifier
- Add analog CD -> Radio harness if not present already
- Modify the radio wire harness using the Metra adapter and connect new amplifiers
- Reconnect battery and enjoy!!!
Hope this helps everyone and sorry to those who were misled by stereo shops who didn’t know better!
Doug
Gustav and M5Board.Com, X5Board.Com & BSW: For hosting and sponsoring so much information it took me 2 months to read and digest it all!
Bob Hazelwood: For providing 95% of the information including full wiring harness details and suggesting this was even possible!
BMWMPWR: For confirming the CD Changer to Radio part number
el_duderino & TJJ (from X5Board): For the X5 analog output information
Dave_GT: For pictures of his non-DSP Eu stereo for comparison
Scott Abel @ MTX: For advice on amplifiers, subwoofers, speakers
The screen in the front of the car is simply a dumb terminal that passes commands to the 4 units in the back: radio receiver, navigation, cd changer, and amplifier. In a DSP vehicle, the nav unit is connected to the radio (analog), the radio to the DSP amp (digital), and the CD to either the DSP amp (digital) or the radio (analog). The output from the radio unit is 2 channel (front) only and does not vary with volume. All modifications to the sound (volume, fader, treble, bass, DSP equalizer, etc) are controller by the amplifier which then provides 10-12 channels of amplification (depending on M-Audio or not).
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