really weird interference
Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=119809
Printed Date: May 13, 2024 at 2:05 AM
Topic: really weird interference
Posted By: naz14
Subject: really weird interference
Date Posted: February 01, 2010 at 6:18 PM
:errr:My wife just bought an 06 Yukon Denali with a GM. factory AM-FM-XM-cassette-CD sound system. As we drove the car home from Cleveland to Detroit we listened to wonderful FM reception. Halfway home we changed to AM, only to find a Deep Buzzing sound in both the left and right channels. We switched to XM to find the same buzzing, but only in the right channel, the left was fine. I figured the radio had issues. We drove home listening to FM and the next morning I went out to the car, turned on the radio without the engine running, and everything worked great, AM, FM, and XM. I started te engine and the AM and FM sounded great but the XM had a background whining noise in the right channel only. I figured that the XM tuner had an output shielding problem into the main radio amplifier. A pain, but probably correctible! I started driving the car with the AM band on and a loud deep clicking stared coming out of both the left and right speakers, increasing in frequency as the wheels turned faster, At 10 mph the clicking turned into a deep buzz with no hint of a radio. I switched to XM and the same noise came out of the right speakers but not the left. Finally, I switched to FM and everything was perfectly clear. The unwanted noise was directly related to the RPMs of the wheels, not the RPMs of the engine. I am pretty sure the original whining noise in the right channel of the XM tuner is a shielding problem but how the turning of the wheels could knock out both channels of the AM radio and only the right channel of the XM radio is way beyond me. If anyone has any ideas I would really appreciate it. In all of my experience in diagnosing interference and reception, I have never seen, or heard of, the vehicle's drive train being an issue. I almost think this thing is haunted
------------- nazty boy
Replies:
Posted By: tedmond
Date Posted: February 01, 2010 at 7:06 PM
does the car have aftermarket HID (high intensity discharge) systems? you can tell if your lights are VERY bright, and they contain a slight hue or blue ------------- Ted
2nd Year Tier 1 Medical School
Still installing as a hobby...pays for groceries
Compustar Expert
Posted By: oldspark
Date Posted: February 01, 2010 at 9:21 PM
Am radio? That is so oldskool!
But so too is the knowledge that spinning wheels can produce static or charge that then arc etc.
So to with bonnet & boot (trunk) lids - even doors....
Anything conductive that is insulated and not strapped.
I'm not sure why spinning wheels should re-appear if it is a problem - it used to be solved steel wool or wipers under the hub caps (I mean real hub-caps, not wheel caps!). I assume later radios had better filtering and noise rejection, antennas or whatever. Then came FM.
But with modern ABS sensors on each wheel, gearbox sensors etc, it could be some other interference.
But is it emag interference via the antenna or from parallel wires (speaker, power & signaling), or maybe conducted through the wiring thought the power supply?
Alas I run dedicated and separate power and speaker cables - not the vehicle's in-harness wiring.
And I expect the experts like tedmond herein to have the solutions.
(There are many possibilities - weak AM signals; additional cap or inductive filtering, or sheilding...)
I'm probably of little tactical use unless it is one of the classic forgotten issues...
OldFart.
Posted By: i am an idiot
Date Posted: February 01, 2010 at 10:17 PM
The vehicles Speed sense wire could be causing your problem. I have no idea what you need to do to correct it, but it sounds to be related to the speed sense circuit.
Posted By: naz14
Date Posted: February 02, 2010 at 5:21 PM
I'm pretty sure your are right with that assessment but how the interference signal is getting to the radio, specifically the whole AM section and the right channel of the XM section, is what's confusing my laim brain.
-------------
nazty boy
Posted By: i am an idiot
Date Posted: February 04, 2010 at 9:11 PM
If you do not care about the speed sensitive volume control, you may want to try and cut the speed sense wire from the back of the radio. If it is a navigation unit, you will have trouble using the nav in a tunnel or a parking garage, other than that you should see no ill effects from cutting the wire. Cut it far enough back to allow for reconnecting if need be.
| Speed Sense |
|
DARK GREEN / WHITE |
|
(AC) |
|
RADIO HARNESS |
Posted By: naz14
Date Posted: February 04, 2010 at 10:14 PM
Good call! Another reply mentioned the speed sense and I completely forgot about the speed sensitive volume control. I am sure that is the source of my problem and I will confirm it tomorrow. Thanks a bunch to both of you. Hope I can help you someday ------------- nazty boy
|