I am using a desktop (no discrete sound card) with Windows 7 installed. The motherboard's audio is Realtek ALC850 7.1 channel AC'97 audio codec.
Normally, I either used a Altec Lansing (the "big speaker") or the apple's default iPhone earbud for listening anything from the PC. There is this weird thing that I pondered so I decided to ask.
There is a tiny short noise coming out of my earbud occasionally. The noise is noticeable, yet it is not to the point of annoying. The noises seem to occur on the following occasion:
1. randomly even when doing nothing.
2. when I scroll something. (for instance, scrolling a web page up and down will cause the noise)
3. when I highlight an item. (for instance, an icon on the desktop, a bookmark link on Firefox window)
4. during loading something.
I tried reduce the sound volume to 0, but the noise is still there. I tried increase the sound volume to maximum, the noise is also there, but the noise's volume remains the same; it doesn't get louder according to the volume setting. This implies this sound does not come from a usual sound output source. It's as if this is the sound from the computer processing or something else. Is there a way to eliminate this noise?
It sounds like it's probably a grounding issue with your case/motherboard/jack. I have an Antec 1200, and when I connected to the front panel, I would get a high pitched squeal coming through. They sent me a new front panel and it went away. Some fixed on the net were to sand down that front panel's ground due to it being painted.
It could be capacitor whine too, usually is related to dirty power somewhere.
Some people are able to get a headphone extension cord, with a volume control in it, radio shack sells them, and sometimes that is enough to kill the squeal.
You are probably getting EMI, something along the path of the cable is not shielded and is causing interference to it. As was said above it may be an issue with the grounding of your audio connector, or it may be another wire running along side your audio out cable thats causing the interference.
Grounding. You know what? My PC used to be on the first floor with grounding socket created just for it. It is now on the 2nd floor and I used a 3-head to 2-head converter for the 2 holes socket. Yes, no ground on 2nd floor. That must be it.