This document explains how to connect audio equipment to the (iMac Flat Panel).
You can use your iMac's built-in microphone to record sound or give spoken commands to your computer. You can also input sound into your computer from USB audio equipment, such as a USB microphone.
To connect USB audio equipment:
1 Turn the audio equipment on.
2 Lower the volume level on the audio equipment.
3 Connect a USB audio device to one of your computer's USB ports.
4 If necessary, select the device you want to record from in the Sound control panel.
5 Use your favorite sound-recording application to record.
For more information, see the documentation that came with the audio equipment and the sound-recording application.
See technical documents:
31379 "Macintosh: How to Record Sounds Without a Sound Input Port"
75218 "Macintosh: How to Connect Audio Devices to Your Computer"