Fundamentals of silencing your PC
You don’t have to be a noise elliminating freak (like me) to notice that your computer makes all kinds of noises. Some can be tolerated, while others are just too annoying or loud, especially when you try to get some sleep in the same room with your running PC. The components inside your computer are not all electronic and fixed. Some have moving parts, such as your hard drive, CD drives, and cooling fans. Each electric motor is a source of noise and it is a pretty difficult task to muffle the noise somehow without restricting airflow which cools down all the circuitry. Motors also generate vibrations, and these are transmitted to other components and the case; the entire metallic box can act as an acoustic chamber and amplify certain frequencies.
It’s usually easier to prevent noise from appearing than trying to mask it. For example, if you need to buy a hard drive or CD drive which you know is a source of noise, pick a model that is very quiet. For years, Western Digital hard drives were very loud both in idle time as well as when the heads were seeking, reading or writing data, while Seagate drives and more recently Samsung drives made efforts in keeping noises to a minimum through various technologies. Look on the technical specification sheet and look for the noise level; most people cannot hear noises with 25 or fewer decibels (dB) in intensity. 30-35 is more like a whisper, but it can be a difference between a low-frequency and a high-pitched tone, even if it’s almost quiet.
Cooling fans are also a source of noise. As the blades of the propeller “cut” through the air, the friction produces noise. The higher the speed of the fan, the louder the noise will be. Some fan manufacturers research new shapes for blades to minimize noise, but these products come at an extra cost. The rotor and the fan body connect in two points, where manufacturers can use either a ball bearing or a sleeve bearing. Ball bearings are more reliable in time because they are sealed and cannot be affected by dust; they are usually a little quieter than sleeve bearings, too. Look for fans with one or two ball bearings. Your power supply also has at least one fan - look for good quality fans when you purchase the power supply, because you will probably not want to break the warranty seal to clean or replace them.
Dust particles in the air can also attach to the blades unevenly and make the fan vibrate louder and louder. You should visually inspect all fans in your computer every few weeks or months, depending on how clean is the air where you live, and clean the underside of the blades with a damp cloth wrapped around a finger.
Last but not least, your computer case is important. If it is a cheap one, built with thin metal sheets and weak mechanical contacts between parts, it will amplify vibrations transmitted by hard drive and fans into a disturbing low-frequency noise. Pick a sturdy, heavy case made by a reputable manufacturer; attention to details, such as plastic mounting frames for fans, air filters and screwless installation usually indicate a high quality product. Friction also appears when air passes through venting holes of the case; if the holes are small or covered with dense grids, this only means there will be more noise (a soft woosh or hiss) generated there; look for cases which have wide open holes where the fans are mounted.
I have tried all sorts of noise dampening methods, from rubber stand-offs for the case, rubber grommets for screwing hard drive to the case, soundproofing the inside of the case with foam pads - but had little luck with them. Prevention by careful selection of components is a lot more effective. You might want to look for other sites and product reviews concerning silencing a computer, but everything you should know is right here.
