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Audio noise.

Posted: 2007-09-27 04:42pm
by nickolay1
I'm having a problem with my newly constructed system. There is significant and constant noise on the front panel audio. This is not present when my headphones are plugged into the rear. I think this may be caused by interference from my video card. There is additional noise, for example, when I scroll a page in firefox. Furthermore, the noise changes when I'm playing a game.

I think that the front panel audio cable needs to be shielded. Any suggestions on how to accomplish that?

Posted: 2007-09-27 05:08pm
by General Zod
Did you double check to ensure everything is connected properly? And that you have the most up-to-date drivers?

Posted: 2007-09-27 05:10pm
by nickolay1
Yes, everything is connected securely and the drivers are the newest. I'm reasonably certain that it isn't an issue of poor connection, because the sound is otherwise fine. I just wiggled the cable with no effect on the noise. Scrolling this window, however, does produce additional noise.

Posted: 2007-09-27 05:45pm
by General Zod
Were there any sound drivers installed previously that might be causing a conflict? Maybe the hardware isn't entirely compatible with your OS?

Posted: 2007-09-27 05:51pm
by aerius
Check the internal routing of the wires. Keep the audio wires away from video cards, power cables, and other sources of noise as much as possible. Also check for bad grounding, make sure all the expansion cards are securely screwed & grounded to the case, and do the same for the front panel piece.

Posted: 2007-09-27 06:17pm
by Howedar
Wires should cross each other as infrequently as possible, and when parallel should be as far apart as possible. When crossing is required, the wires should cross at as near a right angle as possible.

Posted: 2007-09-27 06:41pm
by Darth Wong
To be honest, the inside of a computer is such a horrendously noisy environment that I can't imagine using analog audio connections anywhere on a computer chassis if you're really serious about audio quality. Take the digital output and run that to an external stereo and you'll be much happier.

Posted: 2007-09-27 06:47pm
by Howedar
The audio cable runs inside a case should be pretty stinking short, although I'm not sure exactly where they put the miniature amp on motherboards with integrated sound. And outside the (presumably all-metal) case, I wouldn't expect it to matter a ton.

But E&M is not exactly my strong suit.

Posted: 2007-09-27 08:34pm
by nickolay1
I just did some additional investigation. My wires were already mostly optimally routed. In an attempt to rectify the problem, I rigged a shield from some aluminium foil and tape, but it reduced the noise marginally. My guess now is that it's probably not the video card but the motherboard itself. The connector, which is unshielded, is adjacent to the heavily shielded (and noise-free) rear panel connector.

Here is a recording (made with a disabled microphone, boosted in software) of what it sounds like: http://www.zshare.net/download/38884470948561/

I suppose it would be a good idea to purchase a discrete soundcard anyway.