Thread: Terrible feedback, can't even hear audio...please help.

Originally Posted by vwgtipowr

I have a headunit that feeds the speakers in the car.
The headunit has AUX in (left/right RCA plugs).
The PC has audio out which is just the stereo type headphone jack plug.
I have a adapter from radio shack that plugs into the stereo headphone type jack and converts the signal to 2 RCA plug. I then have a 10' RCA wire that runs to the headunit and plugs into AUX input.

Currently I have one ground, and that is just the - PS wire. Case is not grounded.

so your HU has RCA IN?

what brand HU?

I've heard of people having big issues trying to use the aux in on a hu from the on board sound.

If you can, spring for a USB sound card, Go from the computer to that sound card then into the HU. See if it improves. I've seen people get them for as little as $20.

Originally Posted by RedGTiVR6

so your HU has RCA IN?

what brand HU?

I've heard of people having big issues trying to use the aux in on a hu from the on board sound.

If you can, spring for a USB sound card, Go from the computer to that sound card then into the HU. See if it improves. I've seen people get them for as little as $20.

Interesting link above.
I will have to try plugging my setup into my wifes Ipod (great idea), see if I have the same issues, if I do then I know it is NOT ground related, and maybe it is as you suggest with the RCA IN to the HU.

The headunit is a "DUAL" I purchased it from Bestbuy for $90. I kind of like it, it gets 3 times as many radio stations as my sony and slpine decks did. So hopefully it isn't an RCA IN issue with the HU. That would suck.

BTW, I used to own a black GTI VR6

fwiw - DUAL is THE bottom of the barrel.

The fact that it gets more stations probably has to do with the install, not the hu.



let us know how plugging in the iPod does for you!

Originally Posted by RedGTiVR6

fwiw - DUAL is THE bottom of the barrel.

The fact that it gets more stations probably has to do with the install, not the hu.



let us know how plugging in the iPod does for you!

Yes, the DUAL is bottom of barrel, but I was trying to keep this project on a tight budget. Basically it is just being used, because it was the only thing at a reasonable price level that had RCA in. I would have used the existing alpine I had if it had some AUX input.

Originally Posted by Jahntassa

Sometimes the way to solve problems with aux-ins on headunits is that you need to have a common ground between the headunit and the computer. The audio cables are carrying ground between the HU and the Computer which is causing a voltage difference between the two (I think that's the right wording)

You could try running a wire from your PC case to your HU casing, that may solve it. Also positioning of the grounds for the rest of the system can sometimes come into play.

Thanks.

I could end up witih 100 wires running from my trunk to the front of the car. I still haven't even starting thinking about my amp and sub yet.

So in the case you are talking about, plugging in the ipod to the headunit from the trunk (where the PC is) will tell me nothing, other than if the HU is just junk.

I have a few scenarios now.
1. HU is crap and doesn't work.
2. PC case ground issue - case needs a better ground.
3. Ground loop issue with PS being ground to existing ground.
4. Lack of common ground between PC case and HU case.
5. RFI or EFI interference, wires routed too closely to eachother.

I don't have as much experience as you guys, but I think I have to lean towards an issue with the case not being ground properly. Only because I do get a little bit of interference on the display, which seems to coinside with the audio interference.

Along with plugging the ipod into the HU, I will also plug some headphones into the PC, make sure it isn't freaking out when isolated by itself.

Originally Posted by vwgtipowr

I would have used the existing alpine I had if it had some AUX input.

many times you can get a connector for Aux in with the ai-net.

It is a lower model one, I'll have to check if it is ai-net capable.
Are they all ai-net capable?

yep, any model starting with CDA has a changer port; get the adaptor and it makes it an rca input