They use regular speakers that are supposedly only sending the sound down (more info in The Verge's hands-on: https://www.youtube.com/watch?v=hCKstxDONWI https:

They use regular speakers that are supposedly only sending the sound down (more info in The Verge's hands-on: https://www.youtube.com/watch?v=hCKstxDONWI https://www.youtube.com/watch?v=hCKstxDONWI )