This is the expert version of the overtone challenge. You'll hear a single tone, and you must identify the overtones present within that tone. They will either be present (on) or absent (off). Your challenge is to listen and determine which ones are present by clicking on the appropriate harmonic.

NOTE: there is absolutely no guarantee that you will be able to determine the fundamental from the prompt. Sometimes you'll hear all even overtones (so you won't know if you're hearing [ 1, 2, 3, and 4 ] or [ 2, 4, 6, and 8 ]) and that's just the luck of the draw. Once you've correctly identified all the overtones, the challenge will reset.