Multi Output Device
1. Open Audio Midi Setup
space and type
Audio Midi Setup. Click on the Audio Midi Setup app to open.
2. Open Audio Devices Window
Audio Devices window does not immediately appear when opening
Audio MIDI Setup select
Audio Devices from the
Windows drop down menu in
Audio MIDI Setup.
3. Create Multi-Output Device
In the lower left hand corner of the
Audio Devices click the
+ icon. Select
Create Multi-Output Device
4. Select Output Devices
In the new Multi-Output device you just created select the audio devices that you want to output audio. It is highly recommended you enable
Drift Correction for all devices except the Clock Source device.
IMPORTANT: Due to issues with macOS the Build-in Output (sometimes called MacBook Pro Speakers or similar) must be enabled and listed as the top device in the Multi-Output. If BlackHole is listed first simply uncheck and recheck the box under
Use to change the order.
5. Set Audio Output to Multi-Output Device
right-click on your Multi-Output device and select
Use This Device For Sound Output. Audio should now be playing through your speakers and through BlackHole.
I can't change the volume of a Multi-Output device
Unfortunately macOS does not support changing the volume of a Multi-Output device but you can set the volume of individual devices in Audio MIDI Setup.