Well, they filed a bunch of patents for audio gear it seems. I guess he is doing the opposite of Apple going from cars in the other direction lol. Microphones, headphones, earphones, digital audio players, sound transmitting apparatus, audio speakers, subwoofers, earpads for headphones, audio interfaces, audio equalizer apparatus, horns for loudspeakers and megaphones. https://gizmodo.com/tesla-might-be-getting-into-headphones-1848410892