Ever notice that wobbly, drunken and underwater sound common in so many contemporary pop songs? In an era of pristine recording quality, music producers are referencing old and impure technologies to add character to their recordings. Digital cassette hiss, tape wobble, and vinyl crackle are intentionally added to productions as a facsimile of "authentic" recording technology. Why the sudden nostalgia? Where does this underwater sound come from? What does it mean? How is it made? Find out on a live episode of Switched On Pop, recorded at Recode's annual Code conference with guest host Estelle Caswell, creator of Vox's Earworm video series.Listen to Estelle's Spotify playlist of underwater intros.  Learn more about your ad choices. Visit podcastchoices.com/adchoices