[cr3ative]

It might not be trivial to achieve technically, but at the point you have multiple speakers dotted around a multi-room space, making them all play the same thing in sync is a fairly obvious idea, which I think is more what is being argued here.

[NotYourLawyer]

Depends how broadly it’s claimed. A detailed claim that gets into the technical specifics of how this is implemented might well be nonobvious. A broad claim that covers all possible ways of synchronizing audio is a tougher sell.