How does an audio effects processor perform pitch shifting?
The old-fashioned charm of modified high-pitched voices has recently been revived by the American movie Alvin and the Chipmunks, based on the popular group and animated series of the same name which dates back to the 1950s. These voices were originally performed by recording speech spoken (or sung) slowly (typically at half the normal speed) and then accelerating (“pitching up”) the playback (typically at double the speed, thereby increasing the pitch by one octave). The same effect can now be created digitally and in real time; it is widely used today in computer music.
KeywordsDiscrete Fourier Transform Audio Signal Frame Shift Frame Length Hanning Window
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