Whining sound driving me nuts

tannie · 05-21-2006, 08:42 PM

Alright, I've read the Faq about 5 times now and i still cant seem to figure it out.
I was able to eliminate all components one by one and ive come down to the conclusion that the whine is caused by my sound card/computer.

I attempted a direct soundcard to amp to speaker/sub setup, but that didn't work out too well. Now I'm just using the inputs on my head unit, whenever I rev the engine the whine gets worse. I directly run 14awg wires from the battery's +12 and ground, and I'm using the ground on the harness. There is no whine when I play dvd's or mp3 from the head unit, but when i switch over to aux-in thats when the whine starts. I've checked to see if it was the audio in on the head unit that was causing the trouble using portable cd and mp3 players. My amp is turned off via fog light switch for test purposes.

Something interesting I found was when I tap the 1/8 plug onto any metal part of the faceplate it makes the same exact sound, but when I completely cut off power/ground from the comp, the buzzing goes away when I tap the faceplate.

Moving the mouse also increases the noise...

This is a good replica of the wiring diagram in my car at the moment, the layout is as pretty close to how it is in my Rsx.

DrewShmoo · 05-21-2006, 09:10 PM

are you running the power cables for your car pc / amp, and the rca cables for your sound along the same side of the car? If so keep them seperate, the power cables will produce interference.

tannie · 05-21-2006, 09:23 PM

Quote: Originally Posted by DrewShmoo

are you running the power cables for your car pc / amp, and the rca cables for your sound along the same side of the car? If so keep them seperate, the power cables will produce interference.

I am running separate 12v cables for the amp and carpc, they're running next to each other but the RCA's are run inside the interior. BTW it cannot be the amp as the problem persists even when the amp is off (I made a switch to cut off power from the amps 12v)

dune · 05-21-2006, 09:57 PM

What device is feeding a signal into the aux-in? Make sure it's power ground is the same location as your head unit and computer. From my experience and the FAQ, noise/whine is a grounding problem (ie. loop) 9 times out of 10.

RedGTiVR6 · 05-21-2006, 10:29 PM

it kind of sounds like it's your cable from your computer to your head unit

what kind of cable is this? is it just your generic $2.00 Radio Shack cable? is it's 1/8" out from the computer > 1/8" in on the head unit as an aux. input?

have you grounded your carPC?

tapping the metal end will do that, check it on your home pc, it will do the same thing, same on most home audio units. You're grounding the cable, which sends a signal to the amplifier which the amplifier then amplifies (funny how that works...lol) One thing to note, do not ever touch the opposite end (the end that plugs into the amplifier) to metal, because from that direction, you have power (plugged into the headunit or the like). Nothing to be had from this bit of trouble shooting, though it is perceptive!

What kind of head unit are you running as well? Brand/year/model/etc.

tannie · 05-21-2006, 10:38 PM

Quote: Originally Posted by Red GTi VR6

it kind of sounds like it's your cable from your computer to your head unit

what kind of cable is this? is it just your generic $2.00 Radio Shack cable? is it's 1/8" out from the computer > 1/8" in on the head unit as an aux. input?

have you grounded your carPC?

tapping the metal end will do that, check it on your home pc, it will do the same thing, same on most home audio units. You're grounding the cable, which sends a signal to the amplifier which the amplifier then amplifies (funny how that works...lol) One thing to note, do not ever touch the opposite end (the end that plugs into the amplifier) to metal, because from that direction, you have power (plugged into the headunit or the like). Nothing to be had from this bit of trouble shooting, though it is perceptive!

What kind of head unit are you running as well? Brand/year/model/etc.

Thanks for your help wtih my problem guys.
I tried using different cables, even tried using high quality monster cables my friend had for some reason...loser

Setup for the audio signal is like this.
Onboard Soundcard ---> 1/8 -----> aux in (left and right) -----> head unit sends to speakers.

It's a ****ty head unit (pyramid sigh....) I'm planning to get a different HU eventually, but it just doesnt seem like it may be the problem since other devices connected to the Aux in work perfectly.

My POS http://www.brilliant-electronics.com...mid_pdvd78.htm

Acura RSX 03

P.S. I figured that tapping the faceplate was relevant because it only causes the sound when +12 and ground are connected to the comp. If power and ground are completely taken away from the comp, tapping the metal faceplate doesnt cause the same whine.

tannie · 05-21-2006, 10:44 PM

Just thought of something, since the onboard soundcard's output touches the same ground as the rest of the board and power supply, I can try to ground the computer case itself-this should also ground the audio signal to the same source as HU.

Running an m10000 m1-atx ampie case 512 mb ram if it matters.

My question is, how should I ground the actual carputer? And could it potentially damage my board?

RedGTiVR6 · 05-22-2006, 07:17 AM

Quote:

have you grounded your carPC?

ViperTech1 · 05-23-2006, 01:20 AM

does the whine get louder at higher rmp's?

tannie · 05-23-2006, 02:08 PM

Yeah the pitch and volume becomes higher as rpm is increased.
I grounded the pc-didnt work.

RedGTiVR6 · 05-23-2006, 02:13 PM

and you're absolutely sure that everything else is grounded properly as well?

2k1Toaster · 05-23-2006, 02:29 PM

I had the same problem. High pitched whine that gets louder and louder with higher RPM. I just jiggled the wires behind the HU and it was fixed. Basically got rid of any loops and twists. I am also using RCA cables from Walmart that I bout for $2. Sound great.
If behind the HU doesn't fix it, then go down through the rest of the wires and seperate, make sure they run next to eachother, but not crossing and such everywhere.
Since it only whines when you have the computer in there, then it is probably a grounding issue like the others said. Do you have a ground loop isolator?
I know how annoying that can be. I also read somewhere that wrapping some wires in tinfoil should be a temporary fix, don't know if it works or not.
I would eliminate the HU as a possible source for the problem because you said it works with other devices.

tannie · 05-23-2006, 03:47 PM

Im not really sure what other grounds I should check besides the HU, Power Supply, pc case, and monitor. I am actually using the ground from the car harness for the HU, I can try to ground it on a chassis somewhere instead, but I highly doubt thats the problem. I was hoping to avoid using an isolator as its just a filter and not a solution, but it doesnt seem like I have any other choice.

P.S. Im gonna try to fiddle aroudn with the wires to see if ti helps.