TJJ is a stud (or how to get fullrange preouts from DSP audio)
 

Confirmed the following today on a 2005 X5 4.8 is with DSP (thanks and shout out to TJJ for sharing the info assertively!)

(NOTE: This also tells non-DSP folks how I would do an amp upgrade in their cars : )

1) If the tuner in the rear is unplugged, and the HU is unplugged, and then the DSP amp is unplugged, and then the tuner is plugged back in, the system sees the DSP amp is gone, and the DSP function in the menu is ghosted, and then disappears completely.

You lose your 7-band EQ and your (BS) room and echo settings - BUT your steering wheel controls still work.

2) The preout from the tuner to the DSP amp is 10V peak to peak testing with a 0dB reference CD track with a 1KhZ sine wave.

3) The tuner in the rear has R preout pins, unstuffed. We did not stuff them but did confirm that they work with the fader.

4) The output is flat as a pancake (almost - there is a fairly standard auto-loudness bump/tilt in the bass at the lowest volumes, which decreases as volume increases until you get to about 1/2 of full volume. Tested this with a 1/3 octave RTA.

5) We tried various ways to interface with this balanced signal with DC offset:

- Soundgate LOCPREA. This one had tons of volume and very little noise, and it had no noise with the gains turned down. With a lot of gain restructuring we might have gotten ALL the noise out (with the EQ/line driver and the amps, we have a lot of input and output level settings to tweak). But the LOCPREA has transformers in it, and they tend to pick up noise in the X5 out of the air (EMI). This also had a slight peak at 80 and a slight rolloff below 50 on the RTA on its outputs.

- Soundgate LOC4.2. This was one that SG thought would rock, but it had more noise than the PREA. It required a ground loop isolator on the output (SG ISO2) to filter the DC content of the signal. However, the GLI has transformers too, and this was also noisy when we used the GLI, just less so. SG says that we should have tapped it right at the output of the tuner module under the load floor, but I couldnt see a neat way to do that. Too bad - it was flat on the RTA.

- Soundgate LOCB.2. Horrid, don't even bother, SG doesn't recommend it anyway. Didn't bother with the RTA.

- Homebrew. We took a set of RCA cables, hacked the ends off, tapped them straight into the wires at the DSP amp, and plugged them into a GLI to take out the noise. We tried the SG ISO2, which sounded great and had NO noise until we stuffed it into the back of the changer area where it had to go. Then we had noise. We ended up using a Stinger GLI in a metal case, but what I really want for this car is a Jensen ISO-MAX (http://www.jensen-transformers.com/ci2rr.html ). These would reject EMI better than any others.

RTA'd marvelously as described above.

I measured the DC content of the signal and it was about 0.8V at max volume with the sine wave test signal. I verified with others that this should be fine as an amount of DC offset.

6) I also listened to the system. Brief recap: Dynaudio System 240 GT F and R, with custom-made crossovers for the front at 2500 Hz, and a DLS 10" in a fiberglass box. Genesis 75 x 2 amps F and R and a 300W mono amp for the bass.

First off, more output, so more resolution on the volume control.

Second, clearer, more detailed highs, with more sensation of depth.

Finally, more detail and texture to the bass, with some bass notes very clearly sounding different than they did before. Less thud, more texture. It was as if we'd installed a high-end aftermarket CD player - that's how striking the change was. (The customer had many of the same CDs we'd used to tune the system originally).

Overall, the system seemed to be more transparent. I have to ascribe this to eliminating the distortion in the DSP amp output.

He was unhappy that we had removed his 7-band EQ - but he agreed that it was definitely better sounding. He's going to listen to it for a week and come back for some more work (we are sound damping the doors to make the stereo quieter outside the car).

So how I would do any DSP car now is get a set of 1M to 2F "Y" adapters, hack the male ends off, and wire the female ends into the preout wires at the DSP amp. Then I'd plug in the best GLI I could get, and voila - RCA preouts.

If you're doing this yourself, it really pays to find a sine wave test disc and get a voltmeter. It's easy to find sine wave wires with a voltmeter set to AC.

NOTE: SG theorizes that this does not work with X5s with DSP with the digital cable present. I don't give them a lot of credence because they didn't know this worked until I told them, but this *might* not work on pre-2003 X5 DSP systems. Or it might.

A note on balanced outputs:

Regular RCA cables carry single-ended outputs. These have the outer ring at chassis ground and the (+) center conductor carries the signal.

Balanced lines (like in an XLR connector) work differently. There is a (+) wire, a (-) wire, and a reference ground wire. The signal on the (+) wire is the same as on the (-) wire, but UPSIDE DOWN.

At the other end of a FULLY balanced signal chain, one signal is inverted and then the two are summed together. If any noise is picked up on the cable, inverting the signal puts the signals back inphase, but now makes the noise on one the exact opposite of the noise on the other. If you sum them together, the noises cancel each other out.

So the BMW is balanced (as are many stereo systems) with a twist: a LOT of DC content to the signal. Basically, the signals vary in voltage, but never cross the 0V line, so they're not true AC. We don't care about that if it didn'teventually toast your amp.

So many amps take "balanced inputs". Yes, they do, but they don't do the cancellation thing - they just float the signal ground so you can run these signals straight in. They DON'T use the (-) side of the signal.

So the important thing when working with the BMW preout is to get the DC out and get a signal your amp can use. You can do this with an LOC that has transformers in it, or with a Ground Loop Isolator (they have transformers too). Or you can use a shunt capacitor to ground (like xtant used to tell people to do with BMWs). I've done all of those. Many amps can't take a balanced input, so the LOC can give them a signal that doesn't freak them out.

Hope this helped somewhat...

Nice to hear it worked after all :) For pre-2003 models, with only DSP-cable coming from the cd-changer, you just need to add analog audio cable between the CD and radio, you can get it from your BMW parts dealer.

Reader's Digest Condensed version (by request):

If you have DSP, you can eliminate the DSP and get nice preamp outputs from your X5 OEM head unit to your aftermarket amp.

:thumbup: beautiful write-up!
what does this do for stock wiring? :dunno:
say i wanted to keep the stock speakers and wiring, but wanted only to add an amp for subs; would this work? :dunno:

I don't see that it would... you'd be better off using the sub-only speaker-level outputs of the amp.

When the amp is present the signal from the tuner to the amp stays constant and doesn't change with volume. You don't want your sub to do that.

removing dsp amp
 

exactly how many wires is there coming off the dsp amp that you have to connect to the hacked rca wires.

In other words how many channels do you have coming out the dsp amp that you will have to connect to the aftermarket amps or eq.

el duderino, if you are using a eq like say the "PG ti deq" would it connect after the GLI and before the aftermarket amps?.

el duderino - ok. so, according to ur write-up, does this procedure eliminate the DSP Amp? and so by eliminating the DSP Amp, one would then need to use after-market amps all around? if this is the case, would one be able to use the factory speaker wiring to accomplish this or would one need to run new wires to each speaker? i'm still a little confused.:dunno:

basically, what i am hoping to accomplish in the future (in order of preference) is :

1. add a little more bass. the dlp sub just doesn't cut it, esp. coming out of something w/ 4 - 8" JL Audio's. would it be easier to just tap into the current sub wiring for this?

2. eventually replace the stock mids and highs.

Yes, entirely.

Yes, exactly, this is the purpose of doing this.

BMW speaker wiring is good quality and we frequently use it without any replacement.

If that's all you're doing for now, yes, absolutely. Use a Soundgate LOCHVA. Don't need an LC6 for this.

OK, when you do that, IMO you really should replace the DSP amp too. As my other article/post describes,. the DSP amp is a poor match for ANY aftermarket speakers.

When you do that, you will end up eliminating the DSP amp and rewiring your sub amp for a different source for signal anyway.

Hope that helps.

Sorry, guys, I did not attempt to create a DIY post because it was my understanding that there were already amp wirign diagrams all over this forum for doing wiring, so I didn't really attempt to document any of this. The wires were standard BMW colors if that helps any (so the diagrams should match). If you don't have the wiring diagram, I'd do a one-day sub to the bmwtechinfo site and print the wiring diagrams.

Yes, the EQ goes before your amps, precisely. But FYI, the purpose of the EQ has now changed. (sorry!)

Before you were using it to correct the OEM curve. Now you HAVe no OEM curve. It's flat as a pancake. So you will now use it, IF you still use it, to EQ your sound system.

Sorry I didn't figure this out two weeks before, man (or in my own case, two months!)

:thumbup: u rock! thanks for the breakdown! :thumbup:
that should be quite beneficial.

thanks again,
brian

removing dsp amp
 

in removing the dsp amp and connecting the rca's to the LOC or GLI do you still retain the fader from the head unit?
if not what probably have to be done to be able to fade from front/rear.

thanks

TJJ's posted article by Bob Hazelwood refers to the missing rear output wires. I tested the pins in the empty connector to verify that they work with the fader.

As far as getting the wires to plug in there, I will defer to the article or to someone who's done it.

I haven't done this with the new generation radio connector, but you can open most BMW connectors and add/remove connector pins quite easily. You can get the needed pins/wires if you buy an adapter cable (part number 61126913957) that allows to use a new generation radio in an old generation wiring harness and then just open the connector and remove the pins and put them to your car's radio connector's rear channel pins.

removing dsp amp
 

i have the adapter for the new generation radio which was installed during my sirius retrofit. which pins are you talking about that have to be connected to the rear channel

Radio connector pins for rear channel output:
1. right + blue/viol
5. right - blue/gr
4. left + yellow/viol
8. left - yellow/green

I just looked at BMW schematics for those, so this is not something I have verified. You can do a Google search for NG pinouts and doublecheck those.

OK, I know there are some VERY knowledgeable folks 'round here about the OEM Bluetooth.

When we did the DSP amp disconnect, the Bluetooth stopped working, and we need to get that back online - any suggestions?

Stopped working i.e. no audio? You should change/rewire phone audio and switching/mute wires from DSP-connector to radio's connectors. DSP's 18-pin connector pin 11. tel. audio positive, pin 2. tel audio negative, pin 13. mute. Radio connector X13598 (this connector also receives navi audio, CD goes to the other connector) pin 6 tel. audio positive, pin 12 tel audio negative. Telephone mute goes to main (speaker) connector pin 10. There is also telephone ON signal on this connector's pin 11, I'm not sure what it is. Please doublecheck these from somewhere else before making changes.

We have taken the (+), (-), mute, and on wires over to the tuner box (the mute was actually already present).

We still get no audio in the car. We can hear the occupant over the speaker fine.

I verified the info tjj supplied... but the tuner is not responding.

Either the tuner needs dealer reprogramming for Bluetooth operation, or I need a non-DSP tuner module.

Any thoughts either way?

What does this "We can hear the occupant over the speaker fine" mean? Does the radio get audio from the BT-receiverbox? Have you checked (with scope) if there is audio available all the time during the phone call i.e. is the other callers voice also there but the radio mutes it? Have you adjusted volume with wheel buttons during the call? If nothing else helps, it may be that the BT needs to be reprogrammed for the new audio configuration. I know that the DSP mutes after 40 seconds if it is programmed for non-navi system so maybe the BT does the same. The radio module is the same in all systems.

Sorry that I was unclear (I'm on cold meds).

It should have read "We can hear the occupant over the microphone, on the land line".

I thought that the radio module was the same too. I don't know for a fact that we tested the volume buttons after the mod.

OK, we have now re-wired the BT TelAudio(+), TelAudio(-), and TelON wires from the DSP amp over to the Tuner module. (The TelMUTE wire was already there and in the right place).

We also verified on bmwtechinfo.com what pincs the tel wires were suppsed to be in in the tuner module.

Nada. Zip. Big goose egg. No audio over the speakers. Mute works fine, other caller hears the mic just fine, but BT user gets no BT audio over the speaker.

Suggestions much appreciated.

First you should check if there actually is telephone audio available in TelAudio + and - wires i.e. connect those wires to an extra amp and listen. I'm not sure if TelAudio is a balanced signal but just in case use balanced-unbalanced converter. Where did you connect the Telephone ON signal?

The wiring diagram for a non-DSP signal shows all four wires (audio + and -, Mute, and ON) going into the tuner module.

The DSP wiring diagram shows them going into the DSP (as they did, with the Mute wire showing and testing in both places).

Se we lengthened the + and - and ON wires and inserted them into the correct pins on the tuner module, with the MUTE wire already being present (your pin info was confirmed in the non DSP wiring diagrams on bmwtechinfo.com)

But the tuner module is not passing ANY audio. I am confident it's getting the right signal. Even if it WERE a balanced audio thing, we'd at least get bad-sounding audio.

I've been told that BT installs on non-DSP cars have not required any re-coding.

We get the car back tomorrow AM and if I can't figure this out I have to re-install all those stepdowns and lose the SQ benefits of the straight balanced interface we did. Argh.

We will have a couple of days to work with it, as we are installing an Icelink and possibly a Passport SRX.

But you have not checked if the telephone audio actually is there? I'm just wondering if the BT mutes the audio signal for some reason i.e. it is waiting for the DSP-amp bus signal. So coding would fix this. Also, it may be that the radio still requires coding to actually activate the telephone input. There are weird stuff in this radio, for example the AUX-input appears only after you connect a 300Kohm resistor between input pins. That is if you use a DIY-solution, not the original BMW retrofit cable.

I should have said that we are confident it's getting the right AUDIO signal. I'm not convinced about the rest of it.

We are planning on taking the car in for re-coding Thursday afternoon or Friday. Our testing the first time was compromised in that we didn't have his phone, and we couldn't pair one of our phones because it wasn't accepting the PK on the Moroloa sticker on the BT sheet.

Resolution:

The output is a speaker level output that varies with the volume setting. The level is independent of audio level - when the system mutes for BT, the volume knob controls the BT volume, and after the call is over, the audio system returns to its former level. At least that partially explains why there's no global volume indication...

We tried using a PC speaker amp, but the best solution was a 4 ohm handsfree kit speaker. Plenty of output and sounded great. No wires needed to be run from the BT ULF module to the TUner module - just tap the two twisted blacks that go from the ULF to the DSP amp connector, and there you go.

The next one if these is going to be so effing easy I could spit : )

This one ate our lunch.

The rear outputs worked great on the fader BTW.

i think i know someone that can help.

sorry i wasn't following this thread.

TJJ and el duderino -- i appreciate all the info on this thread. i'll contact someone that may be able to solve your problem.

You mean the Bluetooth thing? Or the DSP cable elimination thing?

Because otherwise, I got no problems : )

And the Bluetooth works GREAT with that external speaker.

actually the info i found out was the need for a separate amp for the BT....

as for the DSP, i know that Janix has a shop in Mass that may have figured it out...

maybe he'll stop by and chime in!

Actually, Sound in Motion didn't use this method for Janix, but he is considering doing what we did when he does an amp swap.

As far as the "need" for a separate amp for the Bluetooth, I also thought that we would need one, but it turned out that we did not need one - and couldn't even make one work the way I expected to. Driving a dedicated speaker worked fine, and as far as the dedicated BT amp, I'm not clear on what it would be good for, to tell you the truth. Is there a specific reason that someone is saying that an amp is required? And is that amp including a speaker? Because they might just be recommending a non-DSP OEM amp that has a Bluetooth input to route the BT audio through the OEM speakers, and that wouldn't help in this instance.

I've talked to Sound in Motion, and they seem like a smart shop, I'd refer friends to them in a second - but I don't think they've got anything on us on this car. Neither S-I-M nor our store were familiar with the DSP bypass trick - it took TJJ to bring it up. And now that we've done it, I will put our ability to upgrade the audio in an X5 with DSP up against any shop in the US.

i wholeheartedly agree about your DSP setup. never seen anyone achieve what you have done with TJJ. kudos to you both.

as far as the BT, I have no working knowledge but asked someone to comment. they may or may not, but they reverse engineered the BT kit to work on pre-03 X5s, and have an indepth knowledge of the BT electronic workings.

keep us posted on your project!

I recently got rid of my DSP amp by using the method descibed here, works great!

Does anybody know the part no for the non-dsp cable to the CD-changer?
I am planning to buy the ICElink, but i'm not sure it will fit straight in to the radio module?

analog cable
 

you may want to contact Tom G. he's your man when it comes to icelink and the analog cable. i did the same bypass with the dsp and being that I had the sirius installed I didn't need the cable being that sirius uses analog signals, but here is the link to the subject previously discussed

http://www.xoutpost.com/stereo-system...t=analog+cable

This thread should really be sticky'ed since this question comes up over and over.

As for the rear speakers, we tapped into the two open pins with some power cables from a computer power source. Worked pretty well and we had them laying around. I have fader control. Too bad I didn't see this write-up when we did the install.

dear all,

As mentioned earlier I got rid of my DSP amp using the procedure described in this thread.
Everything works perfectly and the sound is also great... Until I start the engine.

I tried several LOCS and even purchased the Alto Mobile UI-4 with dedicated balanced-to-unbalanced function. However I keep having problems with alternator buzz. It is not so loud that it is totally unacceptable, however in my opinion alternator buzzez in BMW's do not belong there...

If I disconnect the amplifiers from the UI-4 converter or from the LOC's, the noise is gone.

Would the Jensen ISO-MAX solve my problems????

Any suggestions are wellcome.

many thanks

Michel

I've had good luck with the Jensen ISOmax. Also, did you try different locations for the LOC's? It seems some areas are more "noisy" than others.

well I tried some locations, but I am somewhat bound to the spare-wheel well (cable lengts). Would it make any difference if I put it in another location?? the UI-4 I now use hase a full metal shielded housing?

Where did you mount the isomax?

The IsoMax has each can in a metal cover AND the metal housing. Stay away from the grounding bracket forward of the changer area, on the wheel well.

Thanks for your reply,

But im not sure if I know which grounding bracket you mean?

I grounded all equipment directly to the battery, tried other grounding also, but no difference.

thanks
Michel

There is an OEM bracket with a lot of brown wires coming off of it if you look up there.

You are right, there should be no buzz.

I don't trust Also - former dealer - I think that EMI is probably an issue.

What amps are you running?

Have you checked to see if you have tweeter alternator whine with the system off - including the amps (pull the fuse if you need to, it's an easy way to check). If there is whine with the fuse pulled, the passive crossovers have inductors in them which are picking up EMI from a nearby wire. If the power wire for the amps is right on top of the xovers that will cause the problem. If the fuse pulling doesn't prevent the noise, then pull the xovers out of their current location and get them as far as you can away from the wiring and see if the noise goes away or changes in character.

Hi El,

I certainly did not use the oem ground point with all the brown wires :)

I run the system in full active mode using a Alto Mobile UCS pro digital signal processor/xover with 2 alto mobile PWM amplifiers and one Helix A2 amp for sub...

When the system is turned of, there is no whine. There is also no whine when I disconnect the radio module from the UI-4 bal/un.

I was not implying that you used it. I was telling you to stay away from it. It emits a lot of EMI and anything near it could pick up noise.

So you are using 100% Alto electronics? Hm.

The X5 is the electrically noisest car I've seen in years, and some gear is noiser in that car than other gear. I have to tell you, I'm pointing the finger at Alto. Having tried their gear and having been disappointed with noise rejection and reliability, I have poor expectations.

Is the Helix stereo full range? Is there any chance of temporarily connecting it to the tweeters without the UCS and seeing if the noise goes away?

Alto US used to have a forum for tech help and I remember seeing this sort of thing posted on there.

Hmm,

My signal wires (coming from the ui-4) run very close to the oem-grounding point.
I will try this weekend to route them differently and see what happens to the noise...
Thanks for all help sofar.

Cheers

Please forgive me for reviving this old thread, but I am a visitor from M5Board.com and in the process of replacing my DSP amp with a PDX-5 Alpine amp after stuffing the pins for four channels of pre-amp outs. My issue is that I have Bluetooth and am trying to interpret the above post. Is the upshot that all I need to do is rewire the audio + and - directly to a speaker and voila, my BT will work notwithstanding the removal of the DSP? Put differently, once I remove my DSP, what rewiring do I need to do to preserve my BT? Yes, I am working on a 2001 M5, not an X5, but I have the same guts (updated Bm53 radio, MkIV Nav, same HU, DSP amp, etc.). Thanks in advance.

I have a 2002 non-DSP. A few days ago, I stopped getting audio output from the system. The head unit functions properly, and nothing fell off of the car. I am getting very odd impedance readings from some of the speakers. I don't know what nominal is, but I am getting anywhere from 2-12.6 ohms. I believe a bad impedance situation is causing the amplifier to go into a protection mode (an auto mute, as it were). I understand the difference between single ended and differential outputs, however, on the non-DSP, I am have the same common (brown with red stripe) for all four channels coming from the head unit to the amplifier. This leads me to believe that it may not be a differential (or balanced) output. I am measuring only 6mVDC of offset, and am only reading around 10mVAC for the time-varying measurement. I believe this supports the idea that the amp may be shutting itself down, or perhaps the head unit is shutting down its outputs. Any suggestions are welcome. Specifically, have any of you had any direct experience with the non-DSP, and any idea if one of the JL Audio amps with differential inputs would match well with the head units outputs?