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Scary Sub-Audio Generator

parbly so.

Just came to mind how the air is a 'strange' medium. Perhaps, one could get both 'matching' AND resonance by using a 4 ft by 8 ft panel, or large set of panels, of metal that has a solenoid mounted on it, or a motor with a counter weight on it. All these frequencies are low enough to be mechanically obtainable. AND the sheet of material would be like a large diaphragm. Everyone knows the 'shaking' sheet metal panel used in the days of radio to duplicate storm rumblings.

oops forgot. at low frequencies diaphragms are not so good. The required area gets a bit out of hand. Could do a 'linear' motor along the inside of a tube to create a compression wave. Not sure sound has the most effect. All in all, I think an electric display [flickering lights that try to sync the alpha(?) wave] and low level random noise that the brain tries to make sense of would have more impact at inducing fear response. Or, throw someone into epileptic seizures. Maybe a bit too severe?

Just remembered, not just sound but peripheral vision motion can really induce a fear response. Has something to do with the brain trying to sort out what it can't see directly, only 'sees' motion out of the corners of the eye. The trick is to make a visual 'motion' where a person is NOT looking. Requires using cameras to observe the person, something like that Sony software for interactive TV, and that free vision software to put together the system. Parbly only work on one person at a time, unless you could get an 'en masse' response. ...enough play thinking! BACK TO WORK EVERYWONE!

Reply to
RobertMacy
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Isn't there a company providing such a product? using that principle for advertising products on shelves as you walk through a store, or for informational displays in crowded areas.

Worrisome to me: Don't high levels of ultrasonic cause hearing loss, too?

Years ago a project to keep people away from an area: beaming high levels of ultrasonic simply cause irritation and the subject gets 'fussy' and ultimately will leave.

Reply to
RobertMacy

air is nonlinear, too and becomes a mixer under the conditions of high energy ultrasonics

Some company makes a product that uses that non-linear principle to make 'remote/directional speakers' for advertising, etc.

Reply to
RobertMacy

The costs have skyrocketed, number of personnel has skyrocketed, AND crime rate has plummeted. Not likely to change the trend based upon any of those numbers, seriously.

Reply to
RobertMacy

In one of the buildings on the UF campus, they have ceiling speakers for a row of TVs, but you can only hear the sound in about a 4 ft dia. circle. Step out of the circle and the sound is gone. Pretty cool! Mikek

Reply to
amdx

Someone want to explain what is happening with this fan? To me it looks like the fan blade pitch get adjusted for the frequency it is producing, But what about the RPMs? Thanks, Mikek

Reply to
amdx

I'm thinking the motor is fixed rpm, and just the blades pitch changes with the sound input. So, when there is no sound input, it has a DC output, I don't think it is centered on zero. :-) Mikek Mikek

Reply to
amdx

What about using a shaker speaker fitted to the end cap of a resonant PVC tube?

Here's a great little tutorial.

formatting link

If I used 16Hz, what would be the minimum efficient length for the tube. Given the speaker diameter at its end, it would be costly to use alot of tube that size.

Or is there some other way the speaker couod be mounted?

Richard Clarke

Reply to
rclarke

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