Sound surrounds us, even in the quietest moments. But depending on how we hear, the world can be a different auditory experience for each of us. This episode features four stories from the TED Radio Hour. Twenty Thousand Hertz is produced out of the studios of Defacto Sound and hosted by Dallas Taylor.  Follow the show on Twitter, Facebook, & Reddit. Become a monthly contributor at 20k.org/donate.  If you know what this week's mystery sound is, tell us at mystery.20k.org.  Subscribe to the TED Radio Hour wherever you get your podcasts. Discover more at lexus.com/curiosity. Episode transcript, music, and credits can be found here: https://www.20k.org/episodes/soundandsilence Learn more about your ad choices. Visit megaphone.fm/adchoices