Computer science problems related to music? Are there any CS problems, preferably open, that are related to music or musical theory somehow? I would think of problem with musical notation but also probabilities when randomizing according to a scale or a tonality or general what is considered harmony in frequencies and physics, electromagnetism and waveforms. 

Can you give examples of the area I want to know of?

For instance, given an algorithm that guesses a melody, how successful will the melody be in resembling an artist or likewise decision problem that could be feasible or what do you think?
It is easy to think of many different problems:


Converting sound to scores.
Converting scores to sound.
Automatic music composition.
Music analysis, for example key recognition.
Music classification, such as style recognition and artist recognition.


All of these things are actually being done.