I remember musik in the 1990s at the restaurant I worked at. We had it in the kitchen and a different channel in the seating area. Turn a switch on the wall to change channels, if the kitchen and seating were on the same channel then they had music in sync.

Now this was an entirely hardwired system, and there was no remote. I don't know what sonos's patents are for, but the idea was in place and the difference is do it by wireless computer.