Problem: Can’t get audio in and out at the same time when plug Behringer USB Audio Mixer device such as Behringer U-Phoria UM2 into MacBook Pro. “The selected device has no input controls.” message show in Sound Input setting.
Class-compliant driver in Behringer USB mixers may not work properly with Mac OS X. It show as two separate drivers, one driver contains audio inputs and another driver contains audio outputs. You’ll need to create an aggregate device in Mac OS X using Audio MIDI Setup in order to use input and output simultaneously.
Content Summary
Solution 1: Assign Sound Input in Audio MIDI Setup
Solution 2: Add an Aggregate Device
Reference
Solution 1: Assign Sound Input in Audio MIDI Setup
Step 1: In the Finder, choose Go > Utilities > Audio MIDI Setup. If the Audio Devices window is not visible, choose Windows > Show Audio Devices.
Step 2: Click on USB Audio CODEC 2 in/ 0 out to select it.
Step 3: Click on the Action menu (“gear” icon) and select Use this device for sound input.
Step 4: Note that the microphone symbol has moved to USB Audio CODEC 2 in/ 0 out device.
Step 5: Quit Audio MIDI Setup.
Solution 2: Add an Aggregate Device
Step 1: In the Finder, choose Go > Utilities > Audio MIDI Setup. If the Audio Devices window is not visible, choose Windows > Show Audio Devices.
Step 2: Click Add (+) button on the bottom-left corner in the Audio Devices window and choose Create Aggregate Device.
Step 3: New aggregate device appears in the list on the left side of the window. To rename the device, double-click it.
Step 4: With the new aggregate device selected, enable the checkbox labeled Use on the left side of the Audio Devices window. Do this for each device you want to include in the aggregate device.
Reference
Apple Support: Combine multiple audio interfaces by creating an Aggregate Device
Audacity: Mac and USB input devices
Sweetwater Knowledge Base: How do I make an aggregate device on Mac OS X?
musictribe KB: Recording- How Do I Create An Aggregate Device In Mac OS?