Have you ever been listening to a song and wondered what key it was in? Have you wondered about songs that change key part way through the song, for a chorus or bridge? Now, you don't have to wonder! We have implemented a neural learning program and made it listen to thousands of songs - just so it can instantly tell you the key of the song you are listening to. It uses the built-in microphone, has auto-noise-cancelling, does not need any remote connection, has built-in calibration and is completely plug and play! Just start the app and let it listen - within a couple of seconds it will be able to tell the current key, and track any changes in real time. You can even see how the note energy changes over time in the dynamic real-time harmonic analyzer - each column represents a different octave! It's hypnotic! You will be amazed how many songs are identified as using a major key - but end-up playing in its relative minor! Or, how many Blues/Rock songs use the A Minor Blues scale for solos - regardless of the actual song key...