Thread: Noise, Noise, and no Noise

Originally Posted by Splash-X

Maybe I misunderstood your first post about positive and negative wires.

So it IS ok to run a positive and negative wire side by side?

it IS NOT ok to run a positive OR a negative accross and speaker wires OR av/usb/etc


I ran out of time on Sunday and got home after it was dark on Monday. I hope to get the proper ground and retest.


A side question Toaster, will this bad ground affect USB as well? I'm thinking that a poor ground may be causing power problems on the USB rail. It doesn't happen often but I sometimes see devices become unrecognizeable (spelling?) . Of course vibrations could cause that but I think it may be the power.


Thanks again for all your info

Oh wow, Ok, here is how you do it..... run a main cable, like 4 guage, from the battery to a fuse, then from the fuse to the distrobution block then to the PC. The ground should be a main ground specified by your car manufaturer. The ground should only be 3 feet in length. If you still here noise, go to Best Buy and pick up 2 ground loop isolators, one for rear speakers and one for front. They are made by Install Edge. They are pricey at 17.99, but they work, with no sound quality and 3 db gain. All others I have tried are muffled. Hope this helps. Although Toaster seems like he is being an @$$, he actually isnt...... at least he didnt post the toaster wiring picture, lol...... LOVE YOU TOASTER, you have always been a good help to me.

Yes an improper ground will cause everything to run awkward.... i tried to bolt my ground to the bottom of the car, my PC ran very slow and most USB devices did not work, turns out the ground cable came off and was dragging on the ground. I then took out the whole driver side interior from front to back and searched for the main ground point that Dodge created for my SUV, bolted on and have had no issues since.

From the battery to the car PC I have a run of less than 8ft using 8 gauge wire with a fused terminal bock.

My noise, as pointed out by both Toaster and Pokki, is most likely caused by the ground loop. My orginal translation of what he said was "running a ground next to a +12V will cause noise". After his latest post I see he means running EITHER the ground OR the +12V over any audio,video or USB will cause noise. This I now get.


If proper ground fails, I have considered a ground loop isolator (as pictured on this page http://www.bestbuy.com/site/olspage....=1122655296186)

Now, the ONLY problem I see from this is I would need to go from the 3.5 speak jack to RCA into the isolator using a 3.5 => RCA cable by Monster (I already have two).

Then on the out of the isolator I would a Female extender for RCA to plug the second 3.5 to RCA into the extender and then the 3.5 into my Aux jack.

So, my parts list would be:

Isolator (http://www.bestbuy.com/site/olspage....=1122655296186)
2x 3.5 to RCA (http://www.bestbuy.com/site/olspage....=1114639085343)
1x RCA Couplers (http://www.bestbuy.com/site/olspage....=1184768166914)


If proper ground does not fix my problem, what are the other possible causes of this "noise"? Assume that the +12V comes up the drivers side and crosses NO other wires. Assume the ground is directly to the seat belt bolt, properly preped with no paint, etc. The audio cable goes directly from the jack to the aux jack, no wires ever cross.

Alternator or battery trying to push to much power through stock grounds. Which is why I often recomend upgrad their ground wires.

Does it matter if you turn the ground loop isolator around? I noticed that the output (female) and input (male) seem to be opposite of what I'd actually need for my Zune/car stereo solution.

EDIT: Nevermind, I just went to Radio Shack and bought a ground loop isolator and it fixed my problems...

One ground fix that could be not too much effort would be to pull a coupla moldings back in vicinity of seat pc is mounted under.

Then, pull the carpet back so you can see some body metal. Grind it with your Dremel or however ya hafta 'till metal shines.

Drill through or at least to install 12-14 sheet metal screw. Use stranded 4-8 ga wire, with proper ring terminals attached and securely screw it up....I mean down, and to the pc neg input.

Dats about as close as you can get to a really nice, close ground. I've had problems, I did what I suggest to you - the fix cured my ground problems, anyway.

Now - anyone know a nice girl...........?

The thread got revived today for the sole question of , is the filter one one? Can it be installed incorrectly in terms of pass-through. He poster wanted to know if he could reverse the direction of the audio to match his current wires and still have it function properly.


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Thanks for the info. After I installed my ground wire and before I had a change to solder my cable to the ground the motherboard died on the carPC and I had to RMA it.

The death had nothing to do with the ground. The boards sound card died shortly after I built the system (I mean, like 3 boots) and I didn't want to mess with tearing it appart to RMA it. Well as luck would have it the thing had other issues later on and I sent it back.

The good news is the motherboard will be here today for me to reinstall the OS, reconfigure everything, and move along.


What is sad is, after all the time I've spent car computing I kind of feel like giving it up. I really only need a DVD player and GPS. If my new setup runs in to problems I'm just going to abandon it and just keep it simple by installing a small DVD player and getting a window mount GPS.




Not that anyone cares, but I started scuba diving and we spent anywhere from 45 mins to near 3 hours one way to get to a site so you can see why I'm bummed that my carPC is gone. My wife enjoys watching movies on the way and I like to listen to the movies I've already seen as I drive. We also had to borrow a gps from a family member to get to the sites. I loved when my car PC did work but I'm just tired of things failing, like the motherboard or a corrupt windows install, etc.

/rant

I'm still having an audio problem. When running the ground loop isolator, I still get engine whine and noise. I have grounded the carPC directly to the chassis of the car where the seat belt connects as suggested. I then used the ground loop isolator. Beleive me, it sounds better but still isn't 100%.

Could the +12V line I took from the radio harness be causing any of this?

At this point things are going beyond my level of experience with the audio portion and I don't know what else to try. Some other people have ordered a module for their stock Mazda radio that adds another aux jack under neat the head unit. Maybe this would work better for me as I wouldn't have to rely on the wiring for the aux jack.

The aux jacks in the Mazda 3 is located in the center console, right next to a cigaret lighter port. This could be the cause of SOME of the noise but I am unsure. The add-on module puts the Aux port right at the HU eliminating any additional wiring.


Does anyone have any other ideas? If the module idea fails I'm considering either taking the car to a audio place for them to do it or to just scrap the idea and install a automotive DVD player and get a small gps.

I've loved the hobby. It has treated me well. At this point, I just want a working system.