What you did get to try is the setup process. Before using the headphones, you had to calibrate them using Nura's phone app. In my test, this process involved spending quite a bit of time adjusting the in-ear portion of the headphones so that they would be able to pick up the sound coming from my ear. Once that was done, the headphones played a series of tones to make my cochlea's hair cells vibrate and produce sounds. These were then picked up by the microphone and analyzed by the headphones.