Since I love playing music on my piano, and because I love programming, I created this:

A program which uses YIN (some kind of FFT algorithm) to create this audio spectrum. It can read from any audio source, be it microphone or the computers audio output. There are 3 lines in the graph at the bottom:
Both magenta lines, both are movable, allow you to just select a part of the audio spectrum to show, which is very useful if you just want to get the chords out of a song, or just the notes.
The cyan line can also be moved, it tells the program the lower limit to calculate the actual notes/chords from the frequency bars (which are calculated by the FFT algorithm).
In the top right of the spectrum is, in magenta color, one single note. It shows the currently loudest frequency as a note.
In the top right corner is a simple image of a one-octave piano. Every note over the cyan line will be shown on this piano. This is very useful for chords.

Since compression will fuck this image up, here is a link: https://i.gyazo.com/fbbee76faecbac3...

What do you think about it? I fucking love it.