Matt
@mattlee
Today's lesson on sound physics: Phase Cancelation When two sound waves are the exact inverse of each other, they cancel out. This is what noise cancellation headphones do. They listen to the sound outside and play it back to you 180 degrees out of phase. The result is perceived silence.
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Mr. Wildenfree 🐺🍵🎵
@mrwildenfree
That’s last part is likely what I was getting at! It’s a “perceived silence”, but not real silence lol — like a deaf person in the middle of a rager… it’s actually still noisy but its not perceived (in this case due to noise cancellation). I think when I heard that optical perception extends past our eyes (such as the skin being able to perceive/recognize light), it made me think about audio being able to be perceived beyond our ears (super obvious when bass vibrates us physically, but I wonder about the acute versions of this)
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Matt
@mattlee
Yeah sound is just changes in air pressure and we perceive it as sound if it is bw 20 and 20,000 hertz. phase cancellation does literally create silence though, as in there is no air pressure changes. If you watch how waves in an ocean interact with eachother, you can see the same thing happen. Sometimes they seem to cancel each other out and sometimes they combine depending on the "phase". Not sure if phase as a term applies to water waves but they work basically the same way
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Mr. Wildenfree 🐺🍵🎵
@mrwildenfree
I’d say it makes sense & the water analogy sticks for me for some reason, but I could see how with air as the medium, the phase cancellation would be more consistent with the idea of it literally creating silence or a cancellation in air pressure changes.
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