Design a set of icons for a guitar-related app.
The app uses frequency analysis on guitar music (microphone or mp3s) to help users figure out how to play songs.
Suggestions for elements to use are the guitar fingeboard (electric or acoustic guitar) and a frequency graph or oscilloscope graph.
The set of needed icons are of sizes:
36 x 36 px
48 x 48 px
72 x 72 px
96 x 96 px
512 x 512 px
Icons should be in .png format. The original (PSD or other) format is also requested.