Audio Devices window of Audio MIDI Setup
Use the Audio Devices window of Audio MIDI Setup to set up audio input and output devices you use with your Mac, such as microphones and multichannel audio interfaces. To open the Audio Devices window, choose Window > Show Audio Devices.
Audio device list
Available devices appear in the list on the left side of the Audio Devices window.
To use a device for sound input or sound output, or to play system sounds, select the device, then choose an option from the Action pop-up menu .
Create an aggregate device or a multi-output device.
If you have several audio devices, you can combine them as a single aggregate device.
If you have several stereo output devices, you can play audio through all of them by creating a multi-output device.
Audio device options
On the right side of the Audio Devices window, set the options for the device you’re setting up.
Clock source is typically set to Default. If there are additional choices, you see a pop-up menu.
Your Mac chooses the appropriate option from the Source pop-up menu.
Click the Format pop-up menu, then choose the sample rate and bit depth settings appropriate for the audio device.
Hardware Rate Converter
If your Mac contains support for the hardware sample rate converter, the Hardware Rate Converter pop-up menu appears in the Input pane. When you choose Automatic, the hardware sample rate converter is turned on if the audio samples coming in are PCM and formatted according to the international standard IEC 60958-3. The hardware sample rate converter is turned off if the input stream is encoded.
If software volume control is available for your device, the Volume sliders appear blue to indicate they’re active. Drag the sliders to set the volume for each channel.
To set up surround (multichannel) speaker configurations, click Configure Speakers, then choose the type of configuration you want.
If an audio device doesn’t appear in the list in the Audio Devices window or doesn’t work, make sure it’s connected correctly to your Mac and that you installed any software included with the device.