Different systems playing same music simultaneously


I have four different systems located in different rooms.
Is there a way to make them play the same music like a multi-room system?
Could I send the signal from one source to all the systems at the same time?
Each system has its own amplifier and speakers.
Is bluetooth an option? Can I use a transmitter and several receivers?
Does anyone have this kind of setup?
128x128migueca
One imagines nobody has heard of the problems associated with multiple speaker rooms or, if they have, assume just because the speakers/systems are in separate rooms they don’t affect each other. Even if they don’t act acoustically. It’s similar to the concept that cell phones in the room degrade the sound. Is that too advanced?
No, not at all too advanced. Knowing that cell phones in the room destroys the sound is, um, like day 1... helllllooooo
Real crying shame Google ceased production of the Chromecast Audio puck.
Great little device.
I have two of them on two different systems and control them from either Google Home or bubble UPnP on my droid phone.
No issues at all.
They see Qobuz, tidal, Spotify and my nas on the PC.
Not bad for $40 a pop of Fleabay.