You can easily turn off the microphone in GarageBand by following these simple steps:
- Open GarageBand and navigate to the Track you want to mute.
- Click on the microphone icon in the track's header. This will toggle the microphone on or off.
- Alternatively, you can right-click on the track header and select "Mute Track" from the menu.
Note: If you're using an external microphone, you may also need to disconnect it from your computer to completely mute the audio input.