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

[el_duderino]

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.

[X5_44_v8_nl]

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

[el_duderino]

Originally Posted by X5_44_v8_nl

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.

[X5_44_v8_nl]

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.

[el_duderino]

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.

[X5_44_v8_nl]

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

[herrubermensch]

Originally Posted by el_duderino

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.

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.

[jtvalusn69]

Originally Posted by el_duderino

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...

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?