Did you know your phone is a really good listener? Apps on your phone might be sending and receiving data over ultrasound. Ultrasonic communication is used for everything from tracking your daily habits to enabling light shows at music festivals. We hear from Yale Privacy Lab's Sean O’Brien and Michael Kwet, and privacy and technology counsel Katie McInnis. We also discuss the more positive uses of data over sound with LISNR CEO and co-founder Rodney Williams.​​​​​​​  Twenty Thousand Hertz is produced by Defacto Sound. Subscribe on ⁠⁠⁠⁠⁠⁠⁠⁠YouTube⁠⁠⁠⁠⁠⁠⁠⁠⁠ to see our video series. If you know what this week's mystery sound is, tell us at ⁠⁠⁠⁠⁠⁠⁠⁠mystery.20k.org⁠⁠⁠⁠⁠⁠⁠⁠. Support the show and get ad-free episodes at ⁠⁠⁠⁠⁠⁠20k.org/plus⁠⁠⁠⁠⁠⁠. Follow Dallas on ⁠⁠⁠⁠⁠⁠Instagram⁠⁠⁠⁠⁠⁠, ⁠⁠⁠⁠⁠⁠TikTok⁠⁠⁠⁠⁠⁠, ⁠Facebook⁠, and ⁠⁠⁠⁠⁠⁠LinkedIn⁠⁠⁠⁠⁠⁠. Join our community on ⁠⁠⁠⁠⁠⁠Reddit⁠⁠⁠⁠⁠⁠. Episode transcript, music, and credits can be found here: https://www.20k.org/episodes/ultrasonictracking Learn more about your ad choices. Visit megaphone.fm/adchoices