Infrasonic Horns / Whistle Can Be Manufactured?

Not my field, but I'm confident that generated frequency is inversely proportional or at least inversely monotonic to horn/whistle dimensions. To go to subsonic frequencies it must be really supersize. S.M.

By far! S.M.

A big sub woofer, 18 in diameter can be an infra sound horn. Even with this, you will need to house this air tight in a big box to prevent back travelling wave from canceling the front wave.

I recommend you get yourself an elephant.

And that is the size of 'whistle' you will need to produce infrasound - hope you have good lungs. I suppose you could build an elephant sized bellows to pump it out by hand.

And just an aside, if you're using it outdoors, you may find elephants responding to your call if they are in the area. Or stampeding. Depending on which call you produce, of course...

Hai artsmith,
Thanks for the comment.I already did study on this,Elephant communicate by making low frequency sounds.
So to chase away an Elephant, i need whistle a size of elephant? any other workable solution to chase elephant using Low frequency?
Actually I am plan to do this infrasonic whistle or any workable device to chase Elephant. Elephant major pest in Farm boundry with jungle here in Malaysia.
thanks

hi Devarajen,

Well, I looked into the existing infrasonic and subsonic pest repellants and the reports are not good:

Why not? First, a sound wave amplitude capable of repelling a pest would also harm humans and other animals. Second, if it is not harmful or painful but only 'scary', a continuously emitted sound wave it will only work for a short time, then the animals learn that it is a feature to be ignored ("habituation"). Third, studies found that ultrasound or infrasound repellents were no more effective than audible range of sound - which is easier to generate than infrasound, for sure, especially outdoors without electric power source.

A sudden loud sound to drive away elephants (gunshot, drumbeat) in the usual way is probably as effective as any infrasound generator you can achieve in the field. See the design for a "banger stick" here. But obviously, this is a conflict strategy where elephants are already invading the fields.

Have you tried "chili fencing"? This is reported to be very effective, and there are several ways of doing it, including barrier crop (only effective when fruiting though) and jute rope drenched in a chili mixture. When the chili fence was maintained, elephants even changed their migratory pattern to avoid it. They really don't like hot pepper...

Besides chili fencing, spotlights and electric fences are also said to be effective, but chili fencing is the only one of these that doesn't require a power source.

Also interesting to note, a scientific assessment of these methods found that lights, electric fences, and chili fences were effective in isolation, but that their effectiveness was compromised when combined with noise. Go figure!

What about ...MICE??

hmmm... there does seem to be some debate about the legendary murophobia, but if the snopes analysis is right, it could be the sound of mice (rather than the sight of em) that gives elephants the jitters.

Recordings of mice squeaking might work ..

but.. as its out in the bush, there is no power, so it would have to be a wind up gramophone.. with an old '78 record.... giving my age away now!!

like this one??

No... it's more like this...

Isn't that the Dolby version?

hey, if there's hand crank radios, why not a crank 'mouse box'? We have the technology... I bet I could crank out a fairly loud signal in the face of oncoming elephants..

mythbusters did a segment on this and it showed that elephants really do avoid mice. not sure why though. that wasn't tested.

First of all, 50 hz is not 'ultrasonic' and isn't a frequency used for cleaning.

See here, for some basic frequency data for cleaning microscopic and submicroscopic particles with ultrasound - that is between 25 kilohertz (25,000 hz) and 250 khz (250,000 hz).

As for 'cleaning' with infrasound, really you may as well use a baseball bat.

Where is your market? In the USA you are not allowed to chase or harass wildlife...

Hi Aurizon,

Thanks for the comment.

My market will be Malaysia & Indonesia,

Really? US so strict?I will not chase elephant in the jungle, if the elephant across by human activities area, then we need a device to chase it back to jungle!! I am not will hurting the animal by hit it manually by stones or woods!

In US market, i notice alot of pest repellant products for Cat, Dogs, Deers & Bears? This product can be sell there?

thanks

The mosquito repellents based on sound are of no value or merit.

They also do not repel mice.

The scientific basis of your product may be flawed?

You can shoot and eat them however. Saves a trip to the supermarket.

try this link for horns, its on the GloblSpec web site

http://www.globalspec.com/learnmore/manufacturing_process_equipment/environmental_instruments_equipment/acoustic_horns

Then follow the link to manufacturers... hope you catch you hefalumps!!

Speaking as someone who has built a few speakers, yes the base cabinets you will need to accomplish your intended purpose will need to be quite large, and pretty solidly 'sonically grounded' in order to propagate and disperse the sound. As far as what exactly you plan on broadcasting in order to accomplish your goal will probably require some pretty thorough testing with the animals in the wild. You might find that you actually trigger a stampeding bull to attack your speaker rather than chasing them away! If you are intent on doing this, I suggest that you acquire some antique Altec subwoofers. There are not any contemporary audio components, which are as efficient as old Altec stuff. They won't be cheap either, as they are genuine antiques. Even if they need to be reconed, they will be worth the expense.

You don't need electricity. You want to scare elephants, using 2-20 Hz vibrations, you don't necessarily need to shake the air, but the ground. Unbalance a drive wheel on a car, jack up the axle and block it securely. Or run a small gasoline or diesel motor at idle, out of balance. A small motor with a big unbalanced flywheel at 600 rpm is 10 Hz. Or take two adjacent blades off a windmill. Or use a 32 foot piece of plastic pipe with wind blowing over the end. Or you could spin it with one end closed. See the Blue Men, or a big pipe organ for details. Loud sounds actually require little energy to produce. I ran an Electrovoice Voice of the Theater folded horn on six watts. You don't need to cancel the back wave, just isolate it resonantly.

I too am curious. There could be low frequency beats from two higher frequency tones, but how would intensity be achieved?

Add me to the list, already. Please tell, Europium, and enlighten us about the method of producing intense infrasound without large apparatus. Tornado's mention of difference waves (or what you will call em) is subject to some constraints.. I'm no physicist, please lay it out (for us lay persons, of course).

I find that snapping my fingers is very efficient at repelling elephants.

I've been snapping them for 40 years, and haven't seen an elephant yet, so it must work!

Seriously, to illustrate the size of device required, a fog horn on a large ship is about 8 hz.

The speed of sound is 346 meters/sec.A speaker cone of 1 wavelength would be 346 meters diameter.(1 h)

A 1/100 meter cone would still be 3.46 meters(100hz), and so on.

Smaller speakers could be used, but efficiency goes down.

That is basically why larger speakers are used for bass, and smaller ones for high frequencies.

You could try a horn from a large semi-truck, using a sudden blast or two might get their attention.

While we are on the subject of whistles and horns, I have a question of my own:

Where can I get a police type whistle that will emit a 17khz. sound?

I hear it is very irritating to teenagers, but inaudible to us old timers.

How about an electronic amplifier that will generate a sawtooth wave at 17 khz and a tweeter that will handle it?I would like to put one in my car to play when a teenager leaves his windows down, car vibrating with amplified base,and making my car vibrate to the same frequency.I would like about 1 gigawatt output, just short of being able to melt his car down to a scrap heap.(Smoking would be sufficient).Or how about an EMP generator that would fry his stereo?Kids have no respect for other's rights nowadays.

Some cities and towns have a noise ordinance, but most do not.

Any suggestions?

Yes.. electronic Mosquito repellant...(google it) there was a whole heap of problem this side of the pond regarding them, because as you say, us old timers can't hear them but the kids can, and it was THIER parents who complained to the police about the local store owners who installed these little devices to repel the troublesome kids from the front of the store as they kept bothering the store customers.

So now, I do believe they are banned on the grounds they are offensive...so check it out before installing one!

I would play around with pipes of various sizes. Stretch a drumhead over one end and strike it with a stick/mallet/solenoid.

Frequencies that low are essentially omnidirectional. I seriously doubt you can make an effective horn for a frequency that low. Further there is a LOT of energy under that waveform curve, generating frequencies that low is going to be a power hungry proposition.

Ultrasonic horns are in the 50 KILOhertz range and above, some are into the MEGAHERTZ range.

A lot of time and research has been done in this "sub-audio" realm, mostly for weapons research by various governments. Be careful, you may discover the fabled "brown noise", or a mating call...yikes!

Tesla was able to effect similar by-products through high frequency work. It was speculated (and lightly researched) to be relative harmonics of the main frequency.

You may be able to find an equivalent relationship for elephants. Dogs howl at various frequencies, for example, but the dog whistle is quite high so as to avoid annoying people so much.

In Russia they keep wolves at bay by playing recordings of other wolf packs howling their territorial howls.

Maybe you could record a big bull elephant doing his territorial braying and stomping and play it back at a louder volume.

The idea has some merit, but keep in mind that, from that side of the elephant come very high pitch sounds, and OP says that is looking for very low frequency vibration. Thus, I am asking: are we looking at the right part of the elephant body for generating low frequency vibrations?

Maritime horns are closer to 80 Hz (and above) since most humans can't actually hear below 20 Hz.

Maritime Horns

Sounds below 20 Hz are easily felt in the chest and lungs and one can easily hear the higher harmonics generated by objects vibrating and rattling in the subsonic sound field.

For a resonant design like an organ pipe, size is an issue.

Note frequency (Hz)

C₂ requires approximately an 8 foot resonator. For C₀ (~16Hz) size would have to be 4 times larger, or about 32 feet long. That is pretty large and it doesn't seem like it would be a cost effective or reliable solution to the problem.

Have you looked into bird cannons ?

This can be very effective for all kinds of creatures. It should be especially effective when it can be triggered by an intrusion event instead of the simple timed mode. Expect complaints if you try to use one near a populated area.

While you might have your math correct there are short cuts to reproducing sound, without having to build the biggest possible bass cabinet. As long as the box is sturdy, and has enough square footage inside you don't have to make it 'long'. Especially when dealing with 'infra-sound'. Firstly, you don't really want a directional horn, because you want those frequencies to propagate omnidirectionally. The box just needs to be 'tied down' to the ground firmly to input those frequencies into the ground rather than the air. That is how the elephants will perceive them, through the ground.

I have a friend that built a 32" subwoofer for a sound system that he installed in a church. It would rival any pipe organ you ever heard! As I recall the box for the subwoofer was only about 12' x 8' x 3', and it sat horizontally to give the most square footage that it could to 'shake' the floor.

I will see if he has time or interest.

As for the power requirements, that may have to be figured out based on the componants used, and the desired range that you wish to project the sound.

What is the email address where I or my friend could reach you?

My Name is Stephen. My friend's name is Dan.

You are correct, i stand corrected: 80Hz, not 8

**&^%&**Decimal points!!

Locate an old solid fiberglass satellite dish, 4 meter dishes were common before DSS systems made them obsolete.Stretch a piece of wet leather over it and allow to dry, as in making a drum.

When you hear Elephants, strike it with a heavy club at a rate of 1 or 2 beats per second.

If they run towards you, change the timing till they run away(Trial and error) or have an unfriend help you determine the repelling frequency.

You should be able to find on line information of the ultrasonic distress or alarm frequency for elephants.Their has been some recent studies done on this.

Good Luck.

Here is a link to elephant communication in general,usually below 20hz.

http://uvamagazine.org/features/article/elephant_speak/

Google has many other references to similar.

From the writings of Michael Garstang, researcher in recorded elephant communications:

"We're all familiar with an elephant's trumpeting and roaring, but a whole lot is going on beneath the threshold of human hearing. In the low-frequency infrasound range, these highly social animals send messages both short and long distances to keep in touch with one another."

Garstang conducted his research in Etosha National Park in Namibia, home to more than 2,000 elephants. In all, they collected and analyzed more than 1,300 elephant calls. "We don't know what they're talking about in detail," he says, "but we're going to get there. We know the meaning of about 70 different calls or phrases, such as 'Let's go,' and 'Are you doing all right?'"

http://www.evsc.virginia.edu/faculty/garstang-michael/

Elephants receive VLF through their feet as well as their ears.Perhaps you should consider coupling the vibration into the ground instead of the air.

Hi all,

We have a serious elehpant attacks in several villages by elephants ...and i m wondering can infrasoinc thearoy would helps us this still

Try this proven method that repels elephants.

No electricity required.

Low tech,and provides a source of income as a bonus.

A Bee Hive Fence!

http://elephantsandbees.com/beehive-fence/

You're welcome.