Very interesting, and this is pretty damn scary if it's real. I'm pretty skeptical on this being real though. It sounds like a horror story for Halloween.

If an infected machine is disconnected from the network, and the speakers removed... how is this going to even possibly transmit? This is some sci-fi stuff right here. Viral transmission via audio is crazy, and I'd LOVE to see anything transmit strictly through audio wave signal alone. The implications behind figuring out how to do that could greatly surpass any of the negative implications behind badBIOS itself. Essentially if this is at all real, the implications would indicate I could construct and then transmit a specific frequency from my smartphone to any machine with a built in microphone on a network and pentest the hell out of that given network. If anything, it's potentially being surface disguised as audio transmission and in reality being transmitted via a wifi signal. A desktop with wired ethernet only, and no speakers should have absolutely no way to transmit anything so long as it has been disconnected from a network.

Either way, if you're not already following @dragosr you probably should if you're in the IT world.