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Periodically we will put up a sound toy that we've devised and are
not part of any ongoing project but that we think is cool or fun. The material
is copyrighted, but if you want to link to this or use it, please email us and
credit us. If you think this stuff is very cool and want to talk to us about
creating custom Ear-Brain Toys for your project, please contact us
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Made You Look!
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.
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The Headstretch
What is it? How does it
work?
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. |
The Eyeball Jitter
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...
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Ghostroom!!!
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. |
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