E82 Logic 7 slight static noise on bass hits

[FunkyTown128]

OK guys, I have had my 2009 128i for 2 full days now, and have been driving pretty much non stop (it's SO fun), but anyway, I have the premium sound with IPOD blah blah blah and I am SO happy to report ZERO problems with my system. I am somewhat of an audiophile and do live sound for a living so I know bad or screwed up sound when I hear it. I listen to a lot of electronic music (Van Buuren, Tiesto, etc...) Mine is crisp, clean and loud. I did go in and turn OFF Logic 7. (I just wasn't digging it). And I adjusted the EQ somewhat, but not much. Guess I can just thank my lucky stars I'm one of the lucky ones.

[siddhartha]

Originally Posted by FunkyTown128

Guess I can just thank my lucky stars I'm one of the lucky ones.

I would recommend you try the .zip file attached here and let us know your results. The sound you are listening for sounds like a very thin piece of metal vibrating. If you have heard ground loops before, you should recognize it immediately. Again, you will only hear the distortion clearly at speeds above 20 km/hr.

[gio]

One thing I know for sure is this problem isn't likely in the radio itself. When I took delivery on my car I noticed this problem. A couple of weeks later I realized that my CD player didn't work at all so I took the 1 to the dealer and they swapped the radio out with a brand new radio. I still had the same problem. This problem exists somewhere in the line driving the rear speaker. It's a bad ground or something and picks up noise from something that is related to car speed (not engine speed!). The theory about the DSC controller makes a lot of sense.

[nobbyv]

Originally Posted by siddhartha

If you have heard ground loops before, you should recognize it immediately.

A ground loop does not have a sound. Occassionally, a ground loop can allow noise on a ground plane to enter an audio system and create noise. However, generally this noise is engine speed dependent and is constant. The noise in this case is neither: the car need only be moving to hear it, but then only on sub ~150Hz bass notes. It does not change pitch or intensitity.

[Bullitt]

Originally Posted by siddhartha

The sound you are listening for sounds like a very thin piece of metal vibrating.

Yes, well described.

[siddhartha]

Originally Posted by nobbyv

A ground loop does not have a sound. Occassionally, a ground loop can allow noise on a ground plane to enter an audio system and create noise. However, generally this noise is engine speed dependent and is constant. The noise in this case is neither: the car need only be moving to hear it, but then only on sub ~150Hz bass notes. It does not change pitch or intensitity.

Actually, a ground loop does indeed introduce a sound. See:

http://www.epanorama.net/documents/groundloop/
http://www.channld.com/hum.html
http://www.bcae1.com/glisoltr.htm

While I agree that usually a ground loop doesn't change in intensity, the distortion we are talking about here actually increases to a maximum intensity at about 20 - 30 km/hr and is very faint at lower speeds. It could be an alternator whine, but my theory is that the problem originates in the grounding of the amp in the back. It is both a high frequency and low frequency amplifier (to power the subs and other speakers), so I image the ground is introduced from the low frequency circuit. Looking at the picture here, you can plainly see multiple brown wires connecting to a common ground point right above the amp. Another source of the problem could be the running of the power cable right along side the speaker cables, as depicted here -- a big no-no in car audio.

Regardless, this is definitely a problem and a big enough one that it significantly hinders my enjoyment of the stereo system. BMW owes us a fix.

[Berduderunner]

Originally Posted by FunkyTown128

OK guys, I have had my 2009 128i for 2 full days now, and have been driving pretty much non stop (it's SO fun), but anyway, I have the premium sound with IPOD blah blah blah and I am SO happy to report ZERO problems with my system. I am somewhat of an audiophile and do live sound for a living so I know bad or screwed up sound when I hear it. I listen to a lot of electronic music (Van Buuren, Tiesto, etc...) Mine is crisp, clean and loud. I did go in and turn OFF Logic 7. (I just wasn't digging it). And I adjusted the EQ somewhat, but not much. Guess I can just thank my lucky stars I'm one of the lucky ones.

hopefully for 2009 it has been fixed... if that is the case we need to find out what if anything BMW did differently so we can get this taken care of.

[imported_TheDude]

To recap the problem: In my car, on bass hits, there would be a buzzy/tinny sound. This was 100% reproducible, present at all volumes, regardless of speed or other factors. My car is a 335, but it sounds like the same problem affects 1-series cars as well.

I just picked up my car from the dealership service and seems that the problem is 100% FIXED. I listened to each of the problematic songs, and cannot hear any issue anywhere.

The better news: *no new parts are needed*. As far as I can tell, the problem is a bad connection. There is no TSB for this, but here is a word-for-word recap of the relevant part of the service invoice:

"Audio is still distorted. Customer left car to be fully diagnosed using customers ipod and specific songs that duplicate the problem well. I tested the ipod in several other vehicles to confirm the problem is with the audio system then removed parts from stock #8PG07342. Tested mulf2 module first and found that the problem is no longer present. No further distortion heard."

In other words, at least in my case, this was a labor-only issue of checking the connections between the iPod and the stereo.

A few recommendations for taking your car in:
- Do a detailed write-up of the problem
- Leave you iPod, along with a playlist of the songs that cause the problem
- If you have them, leave earphones in the car too, so the tech can hear the difference
- Document everything

This literally took me about a 6 round-trips to the service guys, and a couple of notes until they got it right.

Since this does not require any special parts, I would expect you'll get minimal pushback from the dealership, as the cost to them is low as well.

Good luck...

[gio]

Originally Posted by TheDude

To recap the problem: In my car, on bass hits, there would be a buzzy/tinny sound. This was 100% reproducible, present at all volumes, regardless of speed or other factors. My car is a 335, but it sounds like the same problem affects 1-series cars as well.

I just picked up my car from the dealership service and seems that the problem is 100% FIXED. I listened to each of the problematic songs, and cannot hear any issue anywhere.

The better news: *no new parts are needed*. As far as I can tell, the problem is a bad connection. There is no TSB for this, but here is a word-for-word recap of the relevant part of the service invoice:

"Audio is still distorted. Customer left car to be fully diagnosed using customers ipod and specific songs that duplicate the problem well. I tested the ipod in several other vehicles to confirm the problem is with the audio system then removed parts from stock #8PG07342. Tested mulf2 module first and found that the problem is no longer present. No further distortion heard."

In other words, at least in my case, this was a labor-only issue of checking the connections between the iPod and the stereo.

A few recommendations for taking your car in:
- Do a detailed write-up of the problem
- Leave you iPod, along with a playlist of the songs that cause the problem
- If you have them, leave earphones in the car too, so the tech can hear the difference
- Document everything

This literally took me about a 6 round-trips to the service guys, and a couple of notes until they got it right.

Since this does not require any special parts, I would expect you'll get minimal pushback from the dealership, as the cost to them is low as well.

Good luck...

I really hope this is the same problem as what we have been seeing on the 1 but it might be different. Our problem exists on all audio, CD, radio, satellite radio, and aux, and only happens when the car is moving. Also, isn't the Logic 7 in the 3 series very different from the one in the 1 series?

[Rachel]

+1 on t he bass buzz... I'm only 2500 miles from my first service, so I'll just bring them a list of problems

[siddhartha]

Originally Posted by TheDude

"Audio is still distorted. Customer left car to be fully diagnosed using customers ipod and specific songs that duplicate the problem well. I tested the ipod in several other vehicles to confirm the problem is with the audio system then removed parts from stock #8PG07342. Tested mulf2 module first and found that the problem is no longer present. No further distortion heard."

In other words, at least in my case, this was a labor-only issue of checking the connections between the iPod and the stereo.

It looks like the MULF2 (Hands-Free Charging Electronics) module handles all USB components, not just the iPod. Is it possible for you to post the phone number of the dealership's service centre so when I go back to my dealership, they have someone to call? Thanks.

Also, it looks like the module is located here (the thing on the top-right with the Bluetooth logo). Maybe a DIY?

[gio]

Originally Posted by siddhartha

It looks like the MULF2 (Hands-Free Charging Electronics) module handles all USB components, not just the iPod. Is it possible for you to post the phone number of the dealership's service centre so when I go back to my dealership, they have someone to call? Thanks.

Also, it looks like the module is located here (the thing on the top-right with the Bluetooth logo). Maybe a DIY?

I really doubt this is the cause of our problem since I don't have iPod/USB (so I don't have this box) yet I still have the same distortion everyone else is hearing.

[untouchableE82]

Originally Posted by siddhartha

Wow, so other people do have the problem...

I find it is most noticeable on the song "Too $hort - I Need A Freak" about 5 seconds in.

I burned that song as an MP3 onto a CD and the noise is still there. I also burned it as a straight audio track and it is still there also, so it's not the MP3 decoding. I also tried removing the USB stick and the sound is still there on the CDs, so it is definitely not due to the memory stick being present.

The sound is also audible with the DSP set to MUSIC, CINEMA/MOVIE, and OFF.

It will be interesting to see what the dealership can do. It sounds like a difficult problem to diagnose since it only happens when the car is at speed.

I am bringing it in though; it's quite annoying. I would hope everyone else who has the problem will do the same.

when you bring it in though what do you tell them? because i tried to tell them that when i had my car in there for a month..and they said they didnt see any problem with it, so i figured it was just me, but i guess im not alone on this problem

[Zoominrex]

TheDude which dealership in the bay area did you take it to? I have the same issue and maybe if enough cars go into the same dealership that has been able to isolate the problem and fix it, they can suggest or recommend a TSB to the factory.

[imported_TheDude]

Originally Posted by siddhartha

It looks like the MULF2 (Hands-Free Charging Electronics) module handles all USB components, not just the iPod. Is it possible for you to post the phone number of the dealership's service centre so when I go back to my dealership, they have someone to call? Thanks.

Also, it looks like the module is located here (the thing on the top-right with the Bluetooth logo). Maybe a DIY?

Sure thing, here are the guys I used:

BMW of Mountain View
Main line: 650-943-1000

I don't know the name of the service guy that actually did the physical work, however.

[imported_TheDude]

Originally Posted by Zoominrex

TheDude which dealership in the bay area did you take it to? I have the same issue and maybe if enough cars go into the same dealership that has been able to isolate the problem and fix it, they can suggest or recommend a TSB to the factory.

No prob -- see above. ;-)

[gio]

Ugh, I just took my 1 in to the dealer this morning. I took a service guy on a test drive and he seemed like he heard what I was hearing when I was driving but now they are calling me up and telling me they don't hear anything wrong.

I don't really have high expectations that this will be able to be fixed and it is very annoying. At least BMW is aware of this now. Hopefully if enough people complain they will look into it.

Next goal will be to procure an oscilloscope and do some investigating on my own...

[gio]

I just picked up the car from the service department. They deny being able to hear anything wrong but I don't think they drove the car on the highway so it's possible they really didn't hear it. If they did, I don't see how they could miss it. It's so annoying that I've started turning off the radio on the highway.

I don't know what to do. This is simply not acceptable for a premium audio system. I'd like them to at least acknowledge the problem. I guess it's time to start making phone calls and writing letters to BMW of NA.

[nobbyv]

Originally Posted by gio

Next goal will be to procure an oscilloscope and do some investigating on my own...

What exactly are you looking to scope?

[gio]

Originally Posted by nobbyv

What exactly are you looking to scope?

I'm going to look at everything I can (power lines, ground, signals to the speakers, etc) and try and track down the source of the interference. Once I can see some kind of noise that only occurs when the car is moving, I can track down where it could be coming from.

I've been thinking about it and I wonder if there is some interference from a wheel speed sensor. The radio is able to adjust volume based on car speed so perhaps the wheel speed sensor is fed right into the audio system and perhaps that is causing interference (it doesn't make sense that it works that way, but I don't know). The more that I think about it though, the more that I don't think this is the case.

My latest feeling is that the noise is coming through the ground from the DSC controller which is otherwise idle when the car isn't moving. Perhaps the bass hits are drawing a lot of power and cause the speakers to be effected by the noise on the power supply generated by the DSC. Right now this is all just speculation. I won't know anything until I start experimenting.

[Zoominrex]

Originally Posted by TheDude

No prob -- see above. ;-)

cool thats my dealership as well. I'll have to take it in next week.

[atr_hugo]

Thank you TheDude!!