Yes, software like this exists. Using multiple overtones to reconstruct a single note is pretty basic in this field, if you search for "wave to midi" software (

Yes, software like this exists. Using multiple overtones to reconstruct a single note is pretty basic in this field, if you search for "wave to midi" software (for example) you'll find a few that do this. The most advanced right now might be Melodyne [1] (used in the article), which also allows you to pitch-shift the detected notes (and all their partials), without affecting the rest of the sound. However it's quite proprietary, and I don't think the details of their algorithms are available, but it does a good job on a variety of instruments. The polyphonic detection can never be perfect, of course, especially with layered organic instruments such as voice and winds, it becomes impossible to determine what note a particular partial belongs to. [1]: http://en.wikipedia.org/wiki/Celemony http://en.wikipedia.org/wiki/Celemony