As promised, here’s an explanation of that crazy 3D audio I posted a couple weeks ago. Unfortunately, it’s long, and given that human beings are incapable of reading anything for more than 14 seconds on the internet, no one will discover the secret surprise at the end. Too bad!
In case you missed it the first time, here’s the audio again (you must listen on headphones or it won’t work):
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The track in question is a binaural recording, sort of like stereo on steroids (damn you, unintentional pun). Those who attended Aaron Soloway’s MegaFest workshop back in April should already be familiar with the concept, but for those who missed out, here’s an explanation:
Most basically, our brains comprehend the directionality of sound in three ways. The first is by comparing the relative volume between two similar sounds. If someone shoots a gun off to your right, the sound wave from that gunshot will be a lot louder in your right ear than your left; your head “shadows” the sound on your left side. Recording engineers use this phenomenon to their advantage when creating a normal stereo recording for an album or movie or whatever. When they pan that cheesy sax solo over to the left, they’re really just lowering the volume of the sax in the right channel.
Secondly, even though the speed of sound is really fast and your head is so very tiny, your brain can still perceive the delay between the sound of that gunshot hitting your right ear and it hitting your left. You can test this out in any basic audio editing program and a pair of headphones. Take a simple mono recording, copy it to a second track, make sure both tracks are panned to opposite channels, then move one a tiny fraction of a second off. Oh look, I did it for you. Would you say those strings are coming from the right or left? (Listen with your headphones):
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Incidentally, this phenomenon appears in other senses as well. If you stimulate two very close points on someone’s skin with a tiny delay, they will perceive the touch as coming from an entirely different point in the direction of the first stimulation. There are even studies showing the same effect with smell and taste (!).
Unfortunately for those sound engineers, it’s not possible to use this technique in most situations to pan sound, since when you offset two similar sound waves, they start to interact with each other in all sorts of mucky ways.
Both the relative volume and relative delay between two similar waves help us figure out if sounds are coming from our right or left, but not above or below. If we could only figure out the direction of sound from one dimension, we would have gone extinct from zombies bursting out of the ground below us, or pterodactyls diving-bombing us from above (see image below).
That’s where the third technique comes in: using our bizarre-ass ears.
Try to step outside of your myopic human perception for a moment and consider the human ear. Holy moly. They stick out like little radar dishes. Fucked up, blobby, rubbery, convoluted radar dishes. From the perspective of an alien visiting Earth, our ears are probably the weirdest-looking things on our bodies apart from maybe genitals (that’s for a later post).
It turns out everything that makes the ear such a freakshow of human anatomy is exactly what allows us to perceive sounds as coming from above or below. Because the ear is so asymmetrical (ie: weird), different frequencies in sound waves coming from different directions bounce off different parts of the ear in different ways before landing inside the earhole (technical term). The brain can then decode location based on how each element in the sound was affected by the ear. I wish my powers of comprehension and explanation were sufficient to explain it better than that, but there it is: it’s really freaking complicated. It boggles the mind to think about how many calculations must be made just to figure out the difference between a zombie attack (below) or a pterodactyl attack (above).
Anyway, so what the hell does this all have to do with binaural recordings? Well, binaural recordings are made to exactly duplicate those three perceptual techniques to achieve true three dimensional sound.
KU100 Dummy Head used for binaural recording.
Recordists either use a stereo microphone stuck inside a dummy head with perfectly sculpted ears, or they use special microphones that sit inside their own ears while they record. Because the sound has already been filtered through a pair of ears and because of the problems associated with offset waves, you need to listen to binaural recordings in headphones to get the desired effect.
If you want to hear more examples, check out the virtual barber recording that made the rounds on the internet a couple years ago — complete with terrible accents (again, get those headphones back on):
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Update: the link isn’t working anymore. Just Google that shit to find it.
There’s also plenty more at Aaron’s site, including many field recordings and classical music concerts where each instrument’s location appears perfectly in your mind’s eye. Sadly, his site hasn’t been updated since festival-time. Get on it, duder.
For those of you skipping right to the end for the secret surprise: I had sex with your mother. The end.
I’m kind of afraid to go to this because I’m THAT insecure, but this all-night, free, open audio/video jam from SHARE looks incredibly cool and fun and is at 
Third Coast just posted an interview with Lance Dann, the creator of 
