# A whistle fit for a T. Rex



## Jabrosky (Jul 16, 2014)

For the short I'm working on, I need a tool or weapon that could be used to repel a _Tyrannosaurus rex_. For story reasons it needs to be inconspicuous, so I thought I could use something like a dog whistle. That is to say, it would be a special kind of instrument that humans couldn't hear, but it would sound painful to a T. Rex. However, it would work at the opposite sound frequency from a dog whistle. Whereas dog whistles produce high-frequency (or ultrasonic) sound, this hypothetical whistle would produce the kind of low-frequency (or infrasonic) sound that large dinosaurs' ears would have been tuned towards. Assuming this setting is low-magic, would it be possible to manufacture an instrument that made very low-frequency noise? If so, would it resemble a whistle or flute at all?


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## CupofJoe (Jul 17, 2014)

Love the Anti-T-Rex whistle....
A whistle or flute would have to be huge - Alpine horn scale huge even if curled up... and it would take a great set of lungs to blow it...
Something like Bagpipes could be an alternative. They could be inflated with a few breaths and then a drone or pipe played used to make the note. 
Neither would be that speedy... or that subtle to carry...


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## Jabrosky (Jul 17, 2014)

CupofJoe said:


> Love the Anti-T-Rex whistle....
> A whistle or flute would have to be huge - Alpine horn scale huge even if curled up... and it would take a great set of lungs to blow it...
> Something like Bagpipes could be an alternative. They could be inflated with a few breaths and then a drone or pipe played used to make the note.
> Neither would be that speedy... or that subtle to carry...


Ah, crud. I was hoping for something that could be attached to a necklace.



Spoiler: my story as currently planned



My protagonist receives this whistle as a token of gratitude from a hermit she's rescued from Velociraptors. She doesn't believe it has any practical use at first, but once she confronts the T. Rex in the story's climax, she ends up having to use it as a last resort.


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## Terry Greer (Jul 17, 2014)

As CupofJoe says a low frequency device would need to be large - otherwise it couldn't produce the waveform.

But why not a high pitched? I like the whistle idea and high pitched sounds are painful - and small devices can create those.

It might be corny but an Ocarina like device, which is basically a bulbous whistle, might be good.
Alternatively maybee its a slide whistle? I forget what they're called -with a plunger you move to change the frequency. So you have to also manipulate it to get the exact frequency you need? (Maybe different frequencies have different affects or affect different species?)


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## mowque (Jul 17, 2014)

A string instrument would be best if you really want results. Something you can hang around you neck is never really going to get very low, just by the nature of sound.

The following link has a video of the lowest instrument in real life. 

Octobass: The lowest-playing musical instrument ever | 22 Words


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## Jabrosky (Jul 17, 2014)

Terry Greer said:


> As CupofJoe says a low frequency device would need to be large - otherwise it couldn't produce the waveform.
> 
> But why not a high pitched? I like the whistle idea and high pitched sounds are painful - and small devices can create those.



Big Dinosaurs Heard Only Low-Pitch Sounds, Experts Suggest


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## wordwalker (Jul 17, 2014)

Not really a way to get ultra-low frequencies, but I had a sudden idea that the coolest sound to repel dinosaurs would come from a Bullroarer. Picture someone whirling a piece of wood (or other material) on a string, and the sound actually driving off enemies.


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## Jabrosky (Jul 17, 2014)

wordwalker said:


> Not really a way to get ultra-low frequencies, but I had a sudden idea that the coolest sound to repel dinosaurs would come from a Bullroarer. Picture someone whirling a piece of wood (or other material) on a string, and the sound actually driving off enemies.


I see from the article that they have variations of this device coming from Africa. Given the setting's vaguely Central African inspiration, this would work wonderful for my story. I may have to sacrifice the part about it hanging from a necklace though.


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## mowque (Jul 17, 2014)

Not necessarily. A bullroarer is still on a string or bit of twine. You could easily keep it around your neck when you aren't using it.  Still could fit your look, I think. You'll just take it off when you want to use it.


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## Terry Greer (Jul 18, 2014)

I like the bullroarer idea - feels also aboriginal in nature as well.


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## Trick (Jul 18, 2014)

I'm not sure that a Bullroarer would scare a T-rex. I can say one thing for infrasonic sound though. Any infrasonic device loud enough to scare a T-rex would cause the user's internal organs to be torn apart. Infrasonic sound has been weaponized because at above natural frequencies it is very dangerous. Tesla designed infrasonic devices that could have levelled cities, with very little wattage expended. Look up Mark Twain and Tesla together (FYI, they were friends) and you'll find a great story about infrasonic sound. Also look up Dr. Vladimir Gavreau and infrasonic whistles (not what you may be thinking, these whistles were huge and powered by electricity).


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## Jabrosky (Jul 18, 2014)

Trick said:


> I'm not sure that a Bullroarer would scare a T-rex. I can say one thing for infrasonic sound though. Any infrasonic device loud enough to scare a T-rex would cause the user's internal organs to be torn apart. Infrasonic sound has been weaponized because at above natural frequencies it is very dangerous. Tesla designed infrasonic devices that could have levelled cities, with very little wattage expended. Look up Mark Twain and Tesla together (FYI, they were friends) and you'll find a great story about infrasonic sound. Also look up Dr. Vladimir Gavreau and infrasonic whistles (not what you may be thinking, these whistles were huge and powered by electricity).


I thought more about the bullroarer idea and decided that a portable one at least wouldn't produce enough infrasonic sound to drive a T. Rex off as I had thought. Besides, it might work better for the story that my heroine use her own ingenuity to defeat the Rex than some special doohickey that someone else gave to her.


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## Trick (Jul 18, 2014)

Jabrosky said:


> it might work better for the story that my heroine use her own ingenuity to defeat the Rex than some special doohickey that someone else gave to her.



As cool as the doohickey might be, you're probably right.


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## psychotick (Jul 26, 2014)

Hi,

Low pitched is a problem for a small device. But instead of producing a sound designed to hurt a T rex's ear, how about one that either scares it or attracts it. A clapper perhaps, two pieces of wood on an elastic band that when smashed together make a sound like an egg shell breaking - the sound a T rex instinctively fears due to childhood trauma? Or a horn that produces a sound like another T rex about to attack during rutting season - assuming they have such seasons.

Cheers, Greg.


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