What is it? How does it work?

Spatial localization is a very complex phenomenon. We're used to the idea that when need to figure out wher things are we look for them. However our ears are actually just about as good as our eyes in figuring out where a sound is or is moving to if it is the right type of sound. (This is something that owls and other gleaning predators do VERY well.) This demo shows that with properly structured and filtered sound, your ears will localize a virtually moving sound source and your eyes will position themselves to "intercept" the invisible target.

What is it? How does it work?

This is an audio version of those pictures that could be a vase or two faces depending on how you want to see, but this time you will use your ears.  Your ears are very good at detecting noise and your brain is very good at ignoring it unless there is something interesting about it - then it is no longer "noise" but a signal. Headstretch starts out by presenting the same digitally sampled noise sample in each stereo channel. Your brain presumes it is just a single noise field. However, when you impose increasing delays between the stereo channels in the 100s of microsecond range in a stairstep fashion, parts of your auditory brainstem are detecting the very small but increasing difference in time between the two channels. Since your brain is so smart, it insists that the only way that two sounds which are exactly the same could be getting more and more separated is for your head to be getting bigger. Unless it's not, in which the sound is just spreading apart.  The perceptual difference will depend on how you attend to the sounds, just as in a visual figure/ground illusion.

What is it? How does it work?

Not all sounds affect you through the mechanical/neural connection from ear to brain. Some work by exciting resonance in hollow structures. Different parts of your body (your abdomen, eyes, even skull) have different best resonant frequencies. In the eyeball jitter, we've used a carrier tone modulated at the best resonant frequency for the average human eyeball. Notice that it doesn't work as well if you are wearing glasses, although it will work if you are wearing contacts. (It may make your ears twitch too, but that's because of the carrier frequencies). Imagine putting this in your video game as an effect for when your character is driving over a cobblestone road with his pet bats...

What is it? How does it work?

Our own work and a number of recent studies have shown that infrasonic and near-infrasonic sound (<20 Hz) can induce feelings of unease or fear. Some have suggested that the perception of paranormal phenomena are actually based on exposure to infrasonic signals which create a "feeling of presence." Ghostroom is a sound with pseudorandom modulation of very low frequency (<50 Hz) sounds, which, with the proper subwoofer settings, can create momentary infrasonic pulsations. If you loop this for several minutes, the sensation increases.