Horrible engine noise

futuresweets10 · 12-28-2004, 03:22 PM

I have had my computer in my 95 s-10 for a few months now and overall I am happy with it. The computer is mounted directly behind the monitor in the dash and I am useing an external sound card.... When I had my 10.4in touch screen hooked up in my house everything was fine. Now there are 5 white lines on the screen (not to worried about them), but the worst thing is the engine noise. I am a car audio installer by profession so I know its not any of the standard problems (ie, power by RCA's, bad rca's, bad ground, etc). BTW, I have the opus 150. The noise is there anytime the computer is on, even if my HU is on radio or CD. Any ideas?

RedGTiVR6 · 12-28-2004, 05:40 PM

interesting, and you say it can't be the rcas? I'm assuming that since you say you do this by trade you went ahead and used some decent RCAs....

and that your power and signal wires are run as far as possible from each other...

with the DC-DC psu there isn't a need to ground the mobo...

can you take the computer out from behind the dash while it's running? or can you take it out and set it up to run outside of the dash rather?

wondering if maybe haiving everything in such close proximity might have something to do with it???

DRWeside · 12-28-2004, 05:56 PM

by external sound card, do you mean a USB solution?

how is your computer connected to your HU? if it is connected by way of an RCA from your sound card to your HU and you removed this audio connection, do you still hear this noise?

futuresweets10 · 12-28-2004, 11:58 PM

Quote: Originally Posted by Red GTi VR6

interesting, and you say it can't be the rcas? I'm assuming that since you say you do this by trade you went ahead and used some decent RCAs....

and that your power and signal wires are run as far as possible from each other...

with the DC-DC psu there isn't a need to ground the mobo...

can you take the computer out from behind the dash while it's running? or can you take it out and set it up to run outside of the dash rather?

wondering if maybe haiving everything in such close proximity might have something to do with it???

I used some RCA's that I found at the shop, the same ones that we sell for $120.00. The power runs under the truck from the back of the truck (battery is under bed) and up through the floor, and the RCA's run under the carpet. I unplugged all of the rca's and ran new ones on top of the carpet just for testing, and that didnt fix the problem. The computer cant be taken out of the dash.... I am starting to think that it has something to do with the relocation of the radio (the screen is where the radio used to be and the radio is now in the console).

futuresweets10 · 12-28-2004, 11:59 PM

Quote: Originally Posted by DRWeside

by external sound card, do you mean a USB solution?

how is your computer connected to your HU? if it is connected by way of an RCA from your sound card to your HU and you removed this audio connection, do you still hear this noise?

yeah, its a USB sound card. I ran a USB cable from the computer to the center console and put a USB hub on the USB cable. Then I plugged the USB sound card into the hub and ran 2ft RCA's to the aux in on the radio. I havent tried that yet.

got2liv4him · 12-29-2004, 12:01 AM

you sell RCA cables for $120???

futuresweets10 · 12-29-2004, 12:03 AM

Quote: Originally Posted by got2liv4him

you sell RCA cables for $120???

LOL, I have seen RCA's for home audio that are over 400. The ones that I have, we no longer sell, but they are 6 channel RCA's. The ones that we sell now for 120 are 2 channel and I dont even like them. They have a woven fabric type insulation so if they get wet its not good.

Iamthehor · 12-29-2004, 12:12 AM

Quote: Originally Posted by futuresweets10

yeah, its a USB sound card. I ran a USB cable from the computer to the center console and put a USB hub on the USB cable. Then I plugged the USB sound card into the hub and ran 2ft RCA's to the aux in on the radio. I havent tried that yet.

USB cables arent shielded, and hubs are succeptable to noise as well
Try unplugging the sound card and see if noise goes away with the HU on radio.

Also, have any pics? Getting ready to start buying for an install in my 96 S10 and seeing how you've used the space could be helpful

Thanks
Andy

futuresweets10 · 12-29-2004, 12:28 AM

WhiteRabbit · 12-29-2004, 03:16 AM

have you tried ground loop isolators on the RCA conncetors yet? also have you tried isolating the power connections on the amplifier you are using on the speakers that are producing the whine, by dragging in another 12 volt battery or power supply?

your shop might have an extra 12 volt supply sitting around, or surely an extra battery you can borrow for 45 minutes

those would be the two places I would start. For the benefit of the others who will read this, a vast vast vast majority of alternator whine issues in cars come from ground loops, where the outer shield of the RCA cable is grounded and the amp is grounded, and when they sit at two different potential levels, noise is induced.

so in your case, an isolator or regrounding to a different location my help.

also, try this. unplug the RCA cables from the amp, see if the noise goes away. I will assume it does. then try plugging in that RCA cable on top of the carpet, yet unplugged from anything else and see if that induces some static. the RCA cable might act like a giant antenna. and if this is the case, and you figure out a solution for that, lemme know, I havent figured that one out yet :/

but chances are, if your whine is really bad, its from multiple sources, and weve got no choice other than the slow process of isolating and identifying sources, then eliminating them one by one!

RedGTiVR6 · 12-29-2004, 08:28 AM

There are some RCAs that go for $10,000 in the home audio world.....

=]

wizardPC · 12-29-2004, 11:02 AM

Quote: Originally Posted by Red GTi VR6

There are some RCAs that go for $10,000 in the home audio world.....

=]

Jeebus! Those better come with a pair of blondes!

RedGTiVR6 · 12-29-2004, 11:06 AM

lol - when you are spending millions on a home system....you can get all the pairs of blondes you want....hehe

or if blondes aren't your thing....just about anything you want

DRWeside · 12-29-2004, 01:21 PM

if you can figure out WHAT kind of noise it is (e.g. alternator whine), then the solution will be easier. I'm not a a pro-audio installer, but I've installed HUs, amplifiers, sub enclosures, speakers, etc. in more than 10 vehicles and have never had to use noise filters.

Just make sure that you minimize the number of grounding points of your components and you should be fine.

Anecdote: I plugged in a portable DVD player into my cigarette lighter for power and connected the audio out to the aux in on my HU. The alternator noise was ridiculously apparent. If I disconnected the audio, the noise went away. So..... disconnect your soundcard and see if the noise goes away. If it does, then you do have a bad ground.

futuresweets10 · 12-29-2004, 09:47 PM

Quote: Originally Posted by DRWeside

if you can figure out WHAT kind of noise it is (e.g. alternator whine), then the solution will be easier. I'm not a a pro-audio installer, but I've installed HUs, amplifiers, sub enclosures, speakers, etc. in more than 10 vehicles and have never had to use noise filters.

Just make sure that you minimize the number of grounding points of your components and you should be fine.

Anecdote: I plugged in a portable DVD player into my cigarette lighter for power and connected the audio out to the aux in on my HU. The alternator noise was ridiculously apparent. If I disconnected the audio, the noise went away. So..... disconnect your soundcard and see if the noise goes away. If it does, then you do have a bad ground.

I had done that in the past and noticed no difference. Tonight I tried something and it worked.... I ran a ground wire from the chassis to the outer part of the RCA's