For decades, NFL strategy slowly evolved from each team running a dozen different plays, to rigid schemes with coaches sending in orders through codewords and secret signals. Then, one piece of audio technology revolutionized the game. Beginning in the early 1990's, the NFL allowed coaches to speak directly to their quarterbacks through radios in their helmets. What followed was an instant increase in excitement for the nation's most popular sport, spawning a high-scoring era of fast paced offenses. Featuring former Super Bowl winning coach, Dick Vermeil, current LA Rams Head Coach Sean McVay, Bose Senior Project Manager Matt Ruwe, and Bose Distinguished Engineer Dan Gauger. Twenty Thousand Hertz is hosted by Dallas Taylor and produced out of the studios of Defacto Sound. Follow the show on Twitter & Facebook. Our website is 20k.org. Become a monthly contributor at 20k.org/donate. Visit mystery.20k.org to enter this weeks mystery sound. Subscribe to The Truth wherever you get your podcasts. Or go to the truthpodcast.com.  Episode transcript, music, and credits can be found here: https://www.20k.org/episodes/blue42  Learn more about your ad choices. Visit megaphone.fm/adchoices