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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.
The project was to upgrade an M5 DSP system (not M-Audio) w/ new interior separates, main amp, sub amp, and subwoofers. Since upgrading the interior speakers has been documented nicely already, this will cover strictly the addition of the amplifiers and the conversion from DSP to non-DSP.

see MTX504 on Stock Bracket.jpg

As mentioned, I do not have a M-Audio, but do have DSP. I have the 6 disc changer, but no DICE, Ipod, phone, etc. None of that should make a darn bit of difference, however.

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).

My CD Changer was already connected to my radio via the analog connection, so that solved the first part of my problem - getting audio data from the CD to the radio. Determine which setup you have by looking at the CD changer – if you have a round connector and a 4 wire square connecter you have a digital connection. If you have a 4 wire square plug and a 3 wire rectangular plug you have an analog connection. I believe the part number for the analog cd->radio cable is 65-12-8-364-756. The other way to tell is to look at your radio harness: the white plug in the lower right of the picture with a black, yellow, and brown wire is from the CD Changer.

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 new harness wires aren't very long (about 6 inches) but they are well labelled. I took a 3 foot twisted pair RCA cable, cut it in half, and soldered the leads to the Metra harness to create a BMW stock to RCA output harness.

see Radio to RCA.jpg

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: Luckily Scott at MTX was very helpful -- ALL of their amps can accept a balanced input via RCA cables.

I don’t like modifying stock wiring harnesses, so I also tried to find the mating halves of the factory wiring harnesses that attach to the amplifier. They are all Amp/Tyco, but unfortunately all but one are out of production and are not available. Instead I chose to use 6 pin / 4 pin power connectors (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:
  • 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!


Additional Info:

Thanks to the following people / boards that made this possible:
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

DSP Explained
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).
Uncategorized Entries with no category

Amplifier Harness Connections - DSP / non-DSP

Posted 1st August 2009 at 22:04 by DouglasABaker
I get a lot of requests for the use of the various pins in the DSP and non-DSP amplifiers and radios, so I thought I would post them all here with my other reference information.

DSP Information (ALL US vehicles):
Radio Harness Pinouts - DSP.pdf
Amplifier Harness Pinouts - DSP.pdf

Non-DSP Information:
Radio Harness Pinouts - non-DSP.pdf
Amplifier Harness Pinouts - non-DSP.pdf
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Revision to Metra Wiring Harness for Pre-2002 Vehicles

Posted 18th February 2008 at 18:28 by DouglasABaker
It has been brought to my attention that I indicated the incorrect part number for older, round pin style radio harnesses:

The correct number is Metra 71-8590.

The number I listed (70-8590/1) will provide RCA outputs from the wiring harness, which in our case is only helpful if you put in a new head unit.


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Adding Amp to DSP FAQ

Posted 11th September 2007 at 16:39 by DouglasABaker
Updated 13th September 2007 at 17:50 by DouglasABaker (Updated for Wiring and KnuKonceptz Products)
I've had a number of questions regarding adding an amplifier to DSP systems - hopefully this FAQ will cover most questions you may have. This is a continuation of

Q. Why shouldn't I just add a Cleansweep?
Q. What are the advantages of aftermarket amplifiers over stock DSP?
Q. How much power do I need?
Q. What do I need to consider when selecting an amplifier?
Q. What are "balanced outputs"?...
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4 Channel Amp Final Installation Pics

Posted 11th September 2007 at 15:29 by DouglasABaker
Updated 11th September 2007 at 15:37 by DouglasABaker
Couple requests for more pics, so here they are. This is a continuation of

First is a picture of the final installation itself. As you can see, I left the wires a bit long. Next time I'd shorten them all up about 6 inches. No big deal since they tuck down in nicely.
Click image for larger version

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Second picture is the distribution block. All of my installation supplies came from a company called KnuKonceptz...
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Adding Amps to DSP WITHOUT Cleansweeps - Results!

Posted 8th September 2007 at 22:59 by DouglasABaker
Well, I finally completed the final electrical connection for the 1st amplifier, and everything is working great.

I should note that there is very slight alternator whine. Noticeable only at idle with the windows up and the radio off only, I will try to cure it by grounding the radio at the same point as the alternator (at the moment it uses the stock location) or perhaps by a ground loop isolator at a later date. It is so minimal that I'm just not worried about it.

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