[Tiresias]

The logical answer would be the computer being too hot, but this doesn't square with my experience. When I start up my computer, the fan often comes on, even though the casing is cool to the touch.

I'm interested to know because I'm using the internal mic and am getting fan noise.

[jamil5454]

When you start up the computer, it runs through a series of tests that determine all components in the machine are working properly. One of these is to determine that the fans are working properly. You probably don't want to mess with the fan settings at all. The best solution is just to get a cheap external mic solution (like the Griffin iMic).

[jasong]

Actually, the logical answer is heat, hence the fan turning on pretty much with the computer. As soon as power is applied, the components start generating heat that must be disbursed. The temperature of the case doesn't necessarily correlate to the internal temp or the temp of the individual components.

In any case, you'll have to post what laptop you are using because the heat and fan profiles are different for different models (even within the same processor type). If you're looking for a way to run your PowerBook/MacBook without the fan coming on, you're SOL unless you want to fry it. If you are getting fan noise in the mic, and nothing is wrong with your laptop (bad fan, etc.), your only solution is to get an external mic.