How to have two Bluetooth audio outputs on macOS

When traveling with friends or family, it is often useful to be able to see a movie together with a friend on the plane. In order to do this, I need to be able to have two headphones connected. In the olden days, when headphones used mini-jack plugs, this was possible using a splitter or T-jack. With Bluetooth, it must be done in software.

In macOS, this can be achieved by following these steps:

1. Connect both Bluetooth devices.
2. Open the ‘Audio MIDI Setup.app’
3. Create a “Multi-Output Device”
4. Add the two Bluetooth headphones as outputs for the Multi-Output Device.

Note: You can set/change the bitrate of the multi-output device. But this can only be done before you add any output devices. Avoid excess CPU usage by matching to a supported rate of your equipment. If your gear supports multiple rates, you should set the individual devices to a common setting before adding to a multi-device since you can end up with quite unreasonable CPU usage, and that’s assuming macOS will recode the rates on the fly.