This particular patent specifically covers a mesh network of independent playback devices that can be dynamically rearranged into possibly overlapping zones, wi

This particular patent specifically covers a mesh network of independent playback devices that can be dynamically rearranged into possibly overlapping zones, with the volume controls being on a separate device in the local network. That's pretty far removed from a simple hard-wired two-channel audio system. I'm opposed to software patents in general so I also think this should not be patentable, but it's hard to deny that there's a ton of engineering effort required to implement such a system and its not just a matter of adding a few lines of code to an existing audio application.