A few things you can do
First off, JC Lives is right. The hard drive can be a major source of noise. Tom's Hardware (
www.tomshardware.com) recently reviewed several quiet 7200 RPM drives; these might be an option for you.
Many new drives offer noise level management, allowing you to trade some speed (seek time) for lower noise levels. It's only going to make a couple of dB difference, but that could be a worthwhile improvement if the drive noise dominates. See
www.storagereview.com and other hardware sites for more information.
Next, realize that quieter fans are almost always going to move less air. Fan design can make a small difference, but fan speed makes a much larger difference. Less air movement = less cooling, which can lead to fried computer parts. The good news is that many systems are overdesigned, so you can usually get away with slower, quieter fans. But if you've filled up every slot and every drive bay, play with quieter fans at your own risk.
I'd be leery about wrapping up a computer system in blankets or coats for the same reason. You might get away with it for short periods though.
If you have a choice, get the largest, slowest fan that will fit. Larger fans are quieter for the same airflow rating. Unfortunately there aren't many places in most computers where you can fit a larger fan.
When you do swap fans, putting in some padding on the mounting points can help reduce conducted noise. I've used self-adhesive felt for this; you should be able to find this in hardware stores. You could try this trick with the drives too, but remember that you have to have a good ground connection between the chassis and the drive.
PC Power and Cooling (
www.pcpowercooling.com) makes a line of quiet power supplies called the Silencer series. I've used these in Mac clones, and they are indeed very quiet and well built. I can recommend them from personal experience.
Much of the noise from a computer is actually re-radiated noise, from panels buzzing in sympathy with the fans and drives. In another thread, Skippy talked about using Dynamat on the sheet metal and plastic of a computer chassis to quiet it down. Cascade Audio (
www.cascadeaudio.com) is another manufacturer of similar products (I forget who suggested them, but it was here, I think). See your local car stereo emporium.
If the computer sits on a hard surface, such as a desk or a wooden floor, noise and vibration can be conducted through the feet and re-radiated by the desk/floor surface. Felt on the feet will help here too.
Last, even if you've quieted the computer as much as you can, you'll still want to keep whatever noise remains out of your recordings. Locating the computer low on the floor, under a desk, and generally as far away from the mic as possible is a good policy. Point the fans away from the "studio" area, but make sure the air has somewhere to go. Carpet on the floor, and cloth or foam wall coverings around the computer, will help absorb the sound instead of reflecting it.
So, here's the order I'd try these in:
- Location. Moving the computer is free!
- Sound dampening around the computer. Cheap or free, and you don't risk frying the CPU if you don't open it up.
- Dampening materials inside the computer. Still cheap, still relatively safe. Just be careful not to block airflow or short anything out.
- Fans and power supply. Fans don't cost much, but good power supplies -- and fried components -- do.
- Hard drive. Drives are definitely not cheap, and it's a hassle to move all your software and data over.
I hope this helped!
