Eli5 why does fast forwarded video sound find but slowed down sounds echoey?

Question

Eli5 why does fast forwarded video sound find but slowed down sounds echoey?

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Answer 1

Because if you actually slowed down the sound, people would get very deep voices. Stretching the sound but retaining the frequencies instead makes it more intelligible but also echoey. Fast forward just shortens everything, which makes it less echoey, but that often isn’t noticeable since peope tend to try recording with very little echo anyway.