You could have downloaded HarmonEye 1.4 for Mac from our software library for free. The program lies within Audio & Video Tools, more precisely Music Production. This free software for Mac OS X is an intellectual property of Bohumír Zámečník.
From the developer:
HarmonEye is a unique software application that listens to the music, applies some deep math under the hood and shows you the tones and chords being played. The intensity of each tone in an octave is shown as a segment of a circle (like on the clock). A loud tone makes a long red segment.
You may want to check out more Mac applications, such as SongScreen Liquid, which might be related to HarmonEye.