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      12-30-2011, 04:57 PM   #1
daveleach
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E92 logic 7 amp/sub buzzing problem

ive been experiencing some strange noises from speakers in my car for a couple of weeks now.
today its got really bad.
went out to car this morning, unlocked it and heard a buzzing noise from outside it. got in and put fob in and started car. still buzzing.
turned radio up, down and off. still buzzing! reset idrive noise stopped for bout 5 seconds during the reboot process.
got too work turned car off, still buzzing. opened drivers door and the noise quietened down.
finish work, unlock car and again car hear the buzzing from outside.
same story on way home with volume etc no change.
pulled up at home, and left car running, to try and find source of noise.
its the sub under the passenger seat.
could this mean a problem with the logic 7 amp??
guess its not the sub blown as when you turn music up it jsut drowns out the buzzing noise!!

any help??
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      12-30-2011, 06:16 PM   #2
ctuna
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The amplifier stays in standby mode until the car goes to sleep

Try locking the car this should put it to sleep quickly.
Lots of problems have been reported with L7 amps here lately.
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      12-31-2011, 03:34 AM   #3
daveleach
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Yes and when I unlock the car. It starts again.
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      12-31-2011, 07:46 AM   #4
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Try unhooking the amp in the trunk. See if it's the amp itself or a short in the wiring allowing noise to enter the system.
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      01-01-2012, 03:36 PM   #5
daveleach
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I managed to unplug one of the connectors from the amp. The smaller of the 2, one had a red light when I disconnected it.
Couldn't unplug the bigger connector.
The noise has gone, but meant I had no music at all also.
So am guessing this means it's an amp problem?
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      01-01-2012, 03:51 PM   #6
ctuna
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FYI

http://www.bmwgm5.com/Logic7_6941681.htm

If berks is berkley california there is a guy that repairs and upgrades
logic 7 for the 7 series there. He might be able to help you, its different
from the link above. His email address is . The other choice would be and upgrade but it won't be cheap.

http://www.bimmerfest.com/forums/sho...d.php?t=519306

ilya.767@gmail.com

Last edited by ctuna; 01-01-2012 at 03:59 PM.
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      01-01-2012, 05:03 PM   #7
daveleach
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No I'm from the uk.
Posted here to see if anybody else had same problems. And also this gets more traffic than the uk page
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      01-02-2012, 11:43 AM   #8
fdriller9
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Quote:
Originally Posted by daveleach View Post
I managed to unplug one of the connectors from the amp. The smaller of the 2, one had a red light when I disconnected it.
Couldn't unplug the bigger connector.
The noise has gone, but meant I had no music at all also.
So am guessing this means it's an amp problem?
You unplugged the optical connection from the head unit.

I believe the amp is turned on through that connection. That's one of the reasons why you had no sound. That optical cable also carries the audio signals to the amp.

Keep that connection plugged in and disconnect the larger harness. It's a locking lever. You want to pull the locking lever toward the right of the car when you are looking into the trunk. A flat head driver is probably necessary to pry the lever loose. It will slide to the right and toward the front of the car.

If you are getting noise after disconnecting that harness, it's the wiring and you either have a short or some other source of noise entering the system.

If you don't, then it might be the amp, optical cable, or head unit.

Have any friends with a L7 equipped car? Swap the amp out and see if persists.

Also do you keep anything plugged into the aux port? If so, try leaving that disconnected.
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      01-03-2012, 07:38 AM   #9
daveleach
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Have plugged the smaller connector back in, and disconnected the larger one.
No noise from under the seat, and also again no sound from speakers. So guess this amp powers all speakers.
So amp prob seems likely?
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      01-05-2012, 05:25 AM   #10
daveleach
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I removed the other sub and plugged it in the left side and I get the same noise. So it's not the sub blown.
Does this now mean that it's a fault with the amp?
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      01-05-2012, 10:56 AM   #11
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dave - as fdriller said many times already, it does not mean it's 100% a problem with the amp. it could be noise entering the system from somewhere else. for example, if the wire from the amp to the subwoofer is frayed and picking up electrical noise from your other electronics, then that could cause the noise as well. It COULD be the amp, but that is not the conclusive problem yet.

If you have factory warranty, bring it in.

My L7 amp was replaced by the dealer with a refurb unit a few years ago according to my dealer history due to a buzzing noise from the door speakers.

Also to consider, I had one speaker on my e46 giving a buzzing noise only when the car was on. It was the transmission computer, needed to add an in-line filter to alleviate the noise to replace it with a newer model 2003+ transmission computer that was shielded.
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      01-06-2012, 06:02 PM   #12
daveleach
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Fixed!!!!!
No more noise. Fingers crossed that's how it stays.
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      01-06-2012, 07:27 PM   #13
ctuna
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How?

How?
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      01-07-2012, 04:03 AM   #14
daveleach
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To be totally honest I don't know!
I eliminated that it was a speaker problem, then extened the wiring from the connector and played music to that speaker, to see of any noise existed then, which it didn't. So decided to take the amp apart and see if anything obvious inside. Blown capacitors etc? Started putting a meter across them to get readings, and nothing obvious, so put the amp back together and hooked it up and no noise! So not sure what it was!
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      01-07-2012, 12:12 PM   #15
ctuna
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If you can do that you might be able to repair it

In the furture . There is guy In Berkeley , Ca that puts upgraded chips in the output stage and ups the power . He normaly does that on 7 series logic 7 series setups. Glad you got is sorted.
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      11-21-2012, 02:41 AM   #16
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Sorry to bump thread - but I can't post new topics yet (lost post count) and I think this relates.

Today, on my e92 2008 335i coupe with Logic 7 sound package, I am having an issue with my subwoofer under the passenger seat. It seems to be vibrating/buzzing, in an unnatural way. See youtube video I just uploaded below. It starts occurring, not for all bass, but only once the bass gets strong in the song/or high bass setting, then it stays on with ALL the bass until the car is shut off for more than 10 minutes.

Could this be due to the subwoofer failing? wiring problems? problem with amp?

If so would this be covered under my BMW CPO as the original warranty has expired (only ~40k miles, but more than 4 years as of August 2012)?

Thank you for any help.

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