How to stream audio to multiple AirPlay devices I have a MacBook, two Airport Express devices, a SoundBar with AirPlay ability, and a bluetooth speaker. I want to stream this laptop's audio to all devices from any program - at a minimum all the AirPlay devices.

Through iTunes (still running High Sierra on this MacBook) I can select all AirPlay devices, and this works great:



Using the Audio MIDI Setup program I can also set up a Multi-Output Device which plays audio via the MacBook and the Bluetooth speaker:



I can connect one AirPlay device in Audio MIDI Setup, and add it to the Multi-Output Device, but it does not actually send the audio to the Bathroom. Only the MacBook and Bluetooth speaker. 


I am quite happy with just the AirPlay devices, but this only works via iTunes.  As I play most of my music through YouTube Music these days, I am wondering if there is any program that will let me send the computer's audio to all AirPlay devices in this way?  And if possible, to the bluetooth speaker also would be amazing.
I must sound to some others on this site like I'm paid to advertise* Rogue Amoeba ;-))
Basically, if it's Mac audio routing, this is the go-to company.

This is one of theirs I've never needed so never tried, but their stuff is usually absolutely rock solid. Have a look at Airfoil

 

* I'm not, of course, but I wouldn't turn them down if they offered ;)