For centuries all kinds of animals have been using sound to determine distance. For example bats and whales have used echolocation to determine where their prey is. An application that would tell us where something is based on the sound it emits would be groundbreaking. I believe that doing this with adult humans' voice would be easy, but expanding it to all humans and eventually any sound in general would be more challenging. This application could be used for security. For example, if a family used this app, they could program it to alert them if any human's voice is within one yard of their house between 11pm and 5am.