Why is it that when the frequency of of musical note is changed by electronic methods, it doesn't sound good? The further the note is changed the worse it sounds. Changes in lower notes are better than changes in higher notes.
For example, playing a note on a guitar sounds ok, and playing one octave up sounds ok, but if the first note is pitch shifted an octave electronically using an effects unit, although it is up an octave it sounds different, squeaking, a bit distorted and not good. Why is that?
Why they sound like that... well its a long story, first of all, there are plenty of different ways to implement the pitch shifting (in the analog and in the digital domain). The analog ones are a bit limited and the digital algorithms always create this "illusion" of changing the signal fundamental frequency which always sounds a bit artificial.