Choosing a Line-In or Internal Mic for GarageBand in iLife ’11
When using GarageBand in iLife '11 you can connect any type of mono or stereo audio source. Most Mac models offer a line-in connection that accepts a cable with a 1/8-inch stereo mini-plug, which is common in many music-lover households. Thanks to GarageBand in iLife '11 you can connect audio sources such as a CD or DVD player, an electric instrument, an electric guitar, a mono microphone or even a stereo set of microphones.
Here’s how the connections work:
For home stereo gear, all you need to do is find a line-out connection on your stereo system (for line-level output) and connect to it a cable that uses RCA-type left and right (typically marked white and red) stereo plugs or a stereo mini-plug. If you use RCA-type plugs, use an RCA-to-stereo-mini-plug converter or a cable that offers a stereo mini-plug on the other end.
For electric instruments such as guitars and microphones, you can use a phono-to-mini-plug converter such as the Monster Instrument Adapter. It's a short cable that has a mono 1/4-inch phono connection on one end and a 1/8-inch mini-plug on the other end to connect to your Mac’s line-in connection.
However, the sound quality isn’t at its highest level — an electric guitar or microphone produces a low input signal, resulting in low volume when you record. You want a line-level source of audio — either line-level output from your instrument, your microphone, your amplifier, preamp or via an audio interface.
If your Mac doesn’t offer a line-in connection, you can purchase a USB audio input device, such as the Griffin iMic or the Roland UA-30, and use it with the Mac’s USB connection.
The Mac’s internal microphone can also be useful, especially when recording sound effects or ambient sound on the road with a laptop.
After connecting your gear, you need to assign sound input to your Mac’s line-in connection. If you’re using the internal microphone, make sure the sound input is assigned to it.