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If you watch closely enough, everything is a speaker

posted by Jason Kottke   Jan 24, 2018

Using high speed cameras, it’s possible to record the vibrations of everyday objects caused by nearby sounds and reverse engineer the sounds…essentially turning anything that vibrates into a speaker. For instance, if you want to know what a person is saying but can’t hear them directly, you can take a video of the house plant next to them and recover the sound from the micro-vibrations of the leaves. In one example, they filmed a pair of Apple earbuds playing a song and the recovered audio was accurate enough for the Shazam app to identify the song.

The group tested an eclectic selection of materials, including a bag of chips (excellent), a soda can (surprisingly mediocre), and a potted plant (average). They were even able to recreate music playing using footage of the vibrating ear buds. The best material of all was the thin foil wrapper on a Lindt chocolate bar Davis had been snacking on.

The worst was a brick, which they intended to use for measuring experimental error. Even that “did better than we expected it to do,” says Davis.

The last demo is especially clever…they use the rolling shutter effect to essentially overclock the frame rate of regular 60fps video to recover nearby sounds. Wow.