b> WARNING: Before you start troubleshooting remember that you are dealing with electricity that can KILL. http://www.kitchentablecomputers.com/static.php - rules
Only work inside the computer case when the power has been switched off and disconnected. Never open the power source. Some of the below steps recommend removing physical parts within the computer. While in the computer it is highly recommend that you be aware of ESD and its potential hazards You will need to open up your computer to check the back of the input headphones plug look for dusty and bad soldering or loose connections. b> Computer Headphone Jack Has Fuzzy Noise
b> When building a computer system, making headphone and microphone jacks are one area where computer manufacturers use the lowest-cost parts. When it comes to computer audio, no perceivable difference in sound quality exists between that of ordinary parts and higher quality ones. Very low-quality parts, or parts that are installed with sub-par wiring, however, can lead to fuzzy sounds and static on headphones. Symptoms and Component Isolation
Start the diagnosis by using different headphones in the jack. If the fuzzy noise or static problem persists over multiple headphones, even if it doesn't happen with all of them, it's probably within the jack on the computer. This is also probably the case if the static increases when you do other things on the computer, like dragging windows around on screen with your mouse, then stops when you stop dragging windows. Causes
b> The leading cause of headphone jack static is electromagnetic interference from other components in the computer's case. When electrical devices draw current, they also generate a magnetic field. Overlapping magnetic fields cause static. To combat this effect, the manufacturer provides for the components on motherboards to be grounded - the wiring from the microphone jack will have an extra lead that goes directly to a grounding agent. When your computer headphone jack has a fuzzy sound, or static, the ultimate cause is usually bad grounding on the wiring that the jack plugs into. Rewiring The Jack
b> If you're comfortable with a soldering iron, and know enough about electronics and wiring, you can remove the wire to your microphone jack and put in one with heavier shielding, or a better ground. If you're not comfortable with this, a computer repair shop may be willing to tackle this for you; the actual cost in labor is about an hour to an hour and a half of labor time. It may be less if the shop technician is familiar with this sort of repair, as opposed to only knowing how to swap cards on the motherboard. Using Different Ports for Audio
Cheaper alternatives exist than rewiring the headphone jack on your motherboard. One of them is to put in a dedicated sound card - which will cost $15 or so, and you may have a compatible one from an old computer that can be scavenged. This will require researching the make and manufacturer of the card to download compatible drivers off the internet, and then installing them on your computer. If you have an unused USB port, the easiest solution is a pair of USB headphones. This has the advantage of working with future hardware as well.
How to reduce static in my audio http://www.miracletutorials.com/how-to-reduce-static-in-audio/