Analysis of three pitch-shifting algorithms for different musical instruments

Pitch-shifting is a process where the original pitch of the sound is increased or decreased without affecting the length of the sound clip being recorded. Pitch shifters are being embedded in most of the audio processors. They are used to generate desired audio effects while recording sounds and music. Some of the notable uses of pitch shifters are in cartoons and entertainment industry for producing very distinct and unique voice, electronic music to generate melodies, metallic music to generate unnatural sound effects, and so on. However, one of the major problems of the pitch shifting algorithms is that there is not a sole algorithm, which can deal efficiently with all types of music and sounds. Here, we are evaluating the performance of three different pitch-shifting algorithms: pitch shifting via phase vocoder using phase locking, PitchshiftOcean, and pitch shifting via TSM using WSOLA for five musical instruments including guitar, piano, violin, drum, and flute. The objective of this work is to define the changes in some of the spectral and time-domain characteristics of musical instruments because of the pitch-shifting process.