[HotHotLava]

I'm also not a patent lawyer, but for example the multi-room volume control 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.

I would be surprised if that already existed in the 90s? I'd actually already be surprised if network-connected speakers were around back then, let alone all the mesh networking stuff.