Your second sentence pretty much hit the nail on the head, as I was reading your first: I'd create a different "controller" object that glues the SystemMonitor

Your second sentence pretty much hit the nail on the head, as I was reading your first: I'd create a different "controller" object that glues the SystemMonitor and the Speakers together. Then you'd have the neat little "tell, don't ask" in THAT object, instead. (Pretty much what you suggested)