Take a listen to this recording of a shaking matchbox with headphones:
Creepy, huh? The three dimensional effect comes from the filmmaker using a binaural dummy head to record it.
This fake head has a microphone in each ear, so the sounds get reflected through the dummy ears just as they would in nature. Listening back on headphones creates the illusion that these sounds are located in the 3D space around your head.
I bet you thought the wrinkles in your ear were just for looks, right? Actually, they’ve evolved that way to do two important things for you:
They help you identify where the sound is coming from in the 360-degree plane around your head (for those pesky lions sneaking up from behind).- They amplify sounds relevant to you as a human, including the high frequencies of human speech (so you can better understand the grunts of your caveman friends).
The 3d effect is amazing. Apparently, some people actually get a tingly goosebumps sensation (which they call “ASMR”) from this kind of audio. If you search youtube for “binaural ASMR” you can find a whole community of these videos.
I just noticed that, too! Found a strange but interesting subreddit on ASMR.
The matchbox itself was not nearly as unerving as the sound of the guys footsteps.