Internal microphone noise with garageband when recording real instruments

if you're recording from the internal mic, it's always going to pick up extraneous noises, like the fan and hard drive in your computer. there is no way around that.

you'd need to use an external USB mic at the very least to avoid that.

But why record your guit from the built-in mic?
Use the line in with an adapter would bypass the built-in mic.

if the internal mic is active, then you're not recording through the line-in at all, it's one or the other, not both.

to record with the line-In:

http://www.bulletsandbones.com/GB/GBFAQ.html#recordlinein

Robin - I use a file called SOUNDSOURCE - it sits in the menubar and allows you to select which input to use on the fly - good stuff.

that's not going to work on your macBook, only a PPC machine

You're only recording using the built in microphone

What's happening is, you've plugged in your electric guitar but you haven't change the audio driver. You're only being recorded thru the built in mic.

Go to GARAGE BAND>PREFERENCES>AUDIO/MIDI >> Audio Input switch to "Built in input" It will ask you to confirm if you want to change the audio driver. Go to your SYSTEM PREFERENCES (for your computer, not garage band) Now go to SOUND and go to INPUT and select LINE IN and make sure it is turned up.

Now you're recording through line in, not built in mic.

If you get no sound, make sure you make a NEW TRACK with REAL INSTRUMENT option. If you still don't audio, go to the TRACK INFO window in GARAGE BAND and under input select MONO 1 or MONO 2.

This should be all you need to fix your problem. Garage band cannot record Line in and Built in mic at same time, these are separate audio drivers.

Thanks