When watching videos/listening to audio that is sped up the voices are always higher than normal. Why is that?
In: 2
Sound of any specific pitch can be literally represented as a sine wave of air movement over time ([here’s a math program](https://www.wolframalpha.com/input?i=play+sin%28pi*220*t*2%5E%280%2F12%2B1%29%29+) using that fact to play an *a* note). Changing the properties of the sine wave changes the properties of the sound. Making more of the sine wave happen in less time (speeding it up) makes it look identical to a higher pitch’s sine wave ([here’s the same math program](https://www.wolframalpha.com/input?i=play+sin%28pi*440*t*2%5E%280%2F12%2B1%29%29+) playing a note an octave higher. Notice that the ‘time’ on the graph is half as large).
Sounds with non-specific pitches are the same, just instead of a sine wave it’s a lot more complex of a line graph. Speeding it up still shifts the pitch.
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