HOW TO Use your Mac as an AirPlay 2 speaker

Set Airplay Receiver

In the Sharing pane, enable AirPlay Receiver. Then decide whether to limit who can use your Mac for AirPlay, whether just the current user connected to the same Apple ID, anyone on your local network, or everyone.

Set Sound output

Switch to the Sound pane and ensure that its Output section is set correctly to get the best out of the AirPlay output. Here, you’ll probably want to push Output volume to maximum to give full control on your device.

Switch play to Mac

Start playing the track on your device. Tap the AirPlay icon at the foot, and select your Mac as the destination. Agree to this in the notification shown on your Mac, and the audio should switch over immediately.