A common misconception is that this whistle produced a sharp shriek-like sound. However, these sounds credited as the Aztec death whistle are actually produced by much larger reproductions of the whistle. Music archeologist Arnd Adje Both, who has tested the original excavated whistles, reports that the actual sound produced is far softer, describing it as similar to "atmospheric noise generated by the wind."

https://en.wikipedia.org/wiki/Aztec_death_whistle