# Is there a way to make a high pitched musical drum instrument that only can be heard by a dog?

I want to make a musical instrument specifically for my dogfolk or other high pitched sound species that can't be heard naturally by humans.

I also want to know if is there a way to make a drum that would achieve such sounds? Because I want to include the drums as a musical instrument.

Besides I don't know much regarding musical instruments or music in general.

The technology and materials range from prehistoric to the modern era, so no futuristic technology, and it's even better if it is achievable before modern technology.

# Tuning Fork

Okay, it's not a drum, but it is at least a percussive instrument. The higher-pitched ones can be hard to hear for humans unless you touch the handle to your skull or hold the fork very close to your ear, but can definitely be heard by dogs from a greater distance (I speak from first-hand experience on that one). Best yet, they continue to sound for a good while (can last over a minute if you hit hard enough), while other suggestions (microscopic drums) make a sound so short there's almost no point in using them. And a tuning fork is something that already exists and you don't need fancy scientific equipment to make one - just buy one from any music supply store fairly cheap.

• I explained why it can't be a drum. You explained what a perfectly sensible substitution would be. Well done! +1! – JBH Jun 16 at 16:58
• "I speak from first-hand experience" Well, I guess it is true what they say, on the internet no one knows you're a dog! – Glen Yates Jun 17 at 18:42
• @GlenYates I thought about that after the fact, maybe I should've said "second-hand"? "second-paw"? At any rate, I've seen dogs react to a tuning fork - they generally do not approve. – Darrel Hoffman Jun 17 at 18:47

Drums work like speakers, only it's a kinetic impact rather than a magnetic impact that moves the material that moves the air.

All you need imagine is a drumstick striking the left side of the image rather than the magnetic coil shown in the image. That's how drums work.

Several things contribute to this.

• The diameter of the drum. The bigger it is, the easier it is to produce low-frequency sound. Conversely, the smaller it is, the easier it is to produce high-frequency sound.

• The capacity of the drum head to vibrate. If you think about it, the human ear isn't very good at picking up just one cycle of any sound. The fewer the number of cycles available to hear, the larger the amplitude must be to hear it.

The healthy, young auditory system can detect tones in quiet with frequencies ranging from approximately 20 to 20000 Hz. Figure 2-2 displays the standardized average thresholds for detecting tonal sounds of different frequencies when the sounds are approximately 500 milliseconds (ms) in duration. (Source)

This is why very large drums must be hit very hard to be easily heard.

• Third is the ability of the drum head to relax or return to its original position. The faster this can happen, the higher the frequency can be reproduced. If the drum head requires 0.1 ms to return to its original position, the drum itself cannot produce a frequency higher than 10 KHz. This is easily seen from the perspective of the speaker animation above. If the speaker cone can't return to its first position before the magnet sends the next pulse, the cone simply stays at its extended position and stops making sound. Likewise, the drum would stop making sound (all you'd hear is the sound of the drum stick whacking the drum head - the drum itself wouldn't make sound).

It's worth noting that the vibration and relaxation of the drum head are not instantaneous. They slow both in frequency and amplitude. The sound a person hears is not a single frequency, but a series of frequencies in a decaying pattern. The initial strike and the size of the drum create the initial, predominant frequency. It gets quieter and lower from there. This could influence the construction of an ultrasonic drum as the decaying frequency could enter the range of human hearing, although the amplitude may not be high enough for detection. (Useful Reference, see the part about "shimmer")

What is a drum?

Finally, it's worth noting that a drum from the perspective of a musical instrument is something that could be defined as "a musician hits a flexible drum head and the result is a sound not attributable directly to the object used to hit the drum."

• A block of wood isn't a drum because what you're hearing is the sound of the drumstick hitting the block of wood, not the sound created by a flexible surface concussing against air. (Musicians don't refer to wood blocks as drums.)

• Likewise, concrete isn't a drum because 99% of what you're hearing is the sound of the drumstick itself.

• An upturned can is a drum because the metal, though much more ridged than a traditional drum head, is nevertheless concussing the air beneath it.

And steel drums are the best example of what might create an ultrasonic sound. But could one be created that dogs, but not humans, could hear?

An Ultrasonic Caribbean Steel Drum

From this, which has gotta be the end-all analysis of steel drums, we learn:

Another implication of using metal alloys for pan production is the effect of the material properties on the acoustics of the note. For instance, if a note were to be modeled as a circular clamped plate, its fundamental frequency can be expressed as [112]: $$f_{0,0} = \frac{0.467t}{r^2}\sqrt{\frac{E}{\rho(1-v^2)}}$$ where t is the thickness of the note metal, r is the radius of the note up to the clamping boundary, $$\rho$$ is the density of the note metal, E is its Young’s modulus and v is Poisson’s ratio.

From page 29 of that document we get the variables filled and, using a steel thickness of 0.55 mm:

$$f_{0,0} = \frac{1.2696}{r^2}$$

Which, if I've done the math right, gives us a drum head radius of 8mm to achieve a 20 Khz fundamental note.

Conclusion

The answer is no, you can't make a drum that emits a frequency beyond human hearing. The drum head's manufacture (a material with a quick enough recovery capability) and size (8mm and smaller using stainless steel) are physically too small for a creature of the size you're discussing to predictably hit with a drum stick (which must, itself, be smaller than the diameter of the drum head).

• "if I've done the math right" you can't have - If f is inversely proportional to r², a factor of 100 in frequency corresponds to a factor of 10 in r, and a 200Hz steel drum would be quite a bit bigger than 2.6mm in diameter. – Pete Kirkham Jun 16 at 20:05
• @PeteKirkham you're right about that. Good check. The equation matches the source. Let's see if I can find where it went wrong. – JBH Jun 16 at 20:14
• @PeteKirkham it was a units conversion error on my part. I should have used the table on page 28 of the primary report rather than finding a second article. Type 304 Stainless Steel has a sound velocity of 4943 resulting in a drum head of 8mm (better, but still too small). A 200Hz drum head (remember, steel drums) computes to 80 mm (about 3 inches) and that's about right for an low A on the drum. – JBH Jun 16 at 20:23
• Surely you could use a snare-drum like setup, to replace the drumstick with a larger pedal that could be predictably hit? – Chronocidal Jun 17 at 11:43
• Still don't think you'd get much volume out of an 8mm drum, even if you solve the problem of hitting it reliably. If your goal is to be heard from a distance, it would not be very effective unless you hit it quite hard, and in that case you're mostly hearing the stick, not the drum. – Darrel Hoffman Jun 17 at 13:38

Yes, it is possible. Drums make sounds because the drum skins vibrate - just as the membrane in a loudspeaker. The faster the skin vibrates, the higher the pitch. It is quite possible to make drums that make ultrasonic sounds (above 20 KHz). Dog whistles usually make sound in the 23 to 54 KHz range.

Four things affect the pitch of the drum: How big the drum is (smaller gives higher pitch), how tight the skin is (tighter gives higher pitch), the material of the drum skin (steel drums e.g. give higher pitch), and the medium in which sound travels (sounds become more high-pitched in water). The last is probably not relevant here, as I imagine that your dogs are out of water.

Ultrasound drums do exist and are used in e.g. medical scanners. Siemens makes ultrasound drum heads from silicon wafers each one-seventh the width of a human hair. University of British Columbia makes drum heads of polymer resin, the width of a human hair. You will not need this degree of ultrasound to achieve your goal, however. A tiny steel drum with a tight skin should hence be able to provide ultrasonic sounds in the range you need.

A problem could be that it is difficult to achieve a very high volume with such a small drum, but then again, dogs have very good hearing. Another problem is that the drum sounds will be very short - more 'plink' than 'boom', as in a steel drum, but even shorter.

• It's possible to create an object that works in the fashion of a drum that can produce the sound ... but can a musician strike it with a drum stick? I'm not convinced the answer is "yes, it is possible." – JBH Jun 16 at 17:03
• @JBH you can totally strike it with a drum stick. Striking specifically the drum part will take some effort though. speed of sound in air / 20 khz = 1.7 cm. I imagine you could attach the drum to a finger and the drumstick to your thumb. Then aiming shouldn't be hard. As a bonus, you could play the tiniest fiddle in the world with your other hand :D – John Dvorak Jun 16 at 18:03
• @JohnDvorak Corrected math: 8mm drum head. Air speed of sound / frequency is, at best, a measurement of the width of the compression wave and therefore a possible measure of the depth of the drum. Using antenna theory (which might not apply), 1/4 of that number is the smallest measure for the depth of the drum: 42.5 mm. – JBH Jun 16 at 23:16

Does it have to be a drum specifically?

If you play around with a drum kit, you will notice that the cymbals make different sounds depending on where you hit. Hitting the top of the ride or crash cymbals with the tip of the stick will produce very high pitched sounds, and depending on the cymbals you have these sounds may be at the edge and/or above of the human hearing range. The thing is, even though you cannot hear these, you can feel it. It hurts the ear a bit when it is loud.

Remember that dogs pick up sounds from way farther than humans do. If you have a dog at home and it comes when you call it, try calling it by whispering from another room ;) breeds with the most wolf-like ears have the best hearing and can hear you opening the peanut butter jar from across the house. This is all to say that you could strike a special cymbal's top from really far so that no human hears it, but dogs do.

If you must insist on a drum: again with drumkits, the smaller the drum the higher its pitch. The lowest sounds you get come from the floor tom (the big one usually to the right of the drummer) and the bass drum (the one at the center of the kit, which you play with a pedal). The highest pitched one is the small tom, at the tol of the bass drum and to the center left of the drummer.

Make a drum small enough and it will be ultrasonic. If you are close enougg you would hear it being beat - it would be a weak sound though, like the sound a drum with a drum mute or a training pad does. That would be mostly comming from the stick. The drumhead proper would be inaudible for humans. I don't know what size such a drum would have, but it would be really small - way smaller than a tambourine.

If you wish to go electronic: drummers who live in apartments and don't want to be evicted usually play electronic kits, or use drum mutes (a kind of muffler) or training pads. You can attach a piezoelectric transducer to these (the electronic kit uses such transducers by design). A transducer is a device that converts some non-electric sognal into an electric one and vice versa. So you could detect vibration on a mostly muted drumhead or pad and have a computer or smartphone play some ultrasonic sound.

If you like DIY you can actually do this with a Guitar Hero drumset, a PC and a speaker. I did this once, not to play ultrasonic sounds but regular drumkit ones. I know for a fact that the PS3 and X360 drumkits will be detected by the PC as Plug and Play joysticks (with each drum or cymbal assigned to a different button, which is "pressed" when you hit them) - the Wii one will just detect the wiimote, but some special software makes it behave like the other ones. Then you need some software to translate those button presses into sound. There is plenty of MIDI software around, but I don't know if they do ultrasound. You could always code your own, or have someone else do it for you :)

• yeah drum and the similar type of instrument. not cymbals though, since it different from drum kind, i dont know it was considered as the same group. – Li Jun Jun 16 at 8:11

what about very low pitched sounds?

by my calculations, a 40 inch drum should do nicely.

i used mental math using a chart from this link: https://tune-bot.com/tunebottuningguide.pdf

however, for the drum you need, I have an idea what could be perfect: a piezoelectric speaker. You can have a drum machine with this that produces beats in the sound range that only dogs can hear.

• Dogs cannot hear as low-pitched sounds as humans can. The lower bound of dog hearing is 67 Hz, while humans can hear as low as 64 Hz. – Klaus Æ. Mogensen Jun 16 at 12:02
• @KlausÆ.Mogensen: The lower bound for human hearing is one or two octaves below 64 Hz. For example, the hum of AC current (50 or 60 Hz) is perfectly audible for most humans. – AlexP Jun 16 at 17:56
• @KlausÆ.Mogensen The commonly stated range of human hearing is 20 to 20,000 Hz. – Alexandre Aubrey Jun 16 at 19:21

Dogs can hear as high 47,000 to 65,000 Hz. Adult Humans can hear as high as 20,000 Hertz, although young children can hear higher.

You would have to make the drum out of something like copper or aluminum. As they allow vibrate faster therefore allowing the sound to reach a higher Hertz.
Small drum would be required because the bigger the drum the lower the speed of vibrated because of speed from edge back to hit point and vice versa.

Dogs with pointed ears will be able to hear better than dogs with floppy ears. So you have to base the sound on what type of ear will be needing to hear it the most.

Dogs tend to pay more attention to sounds than humans because humans have a thing in their brain that makes it so that they can block out background noise. Although like in people with autism or sensory processing disorder you will see that they cannot block out background noise. So, all the noise sounds at the same level of loudness. So, the sound would not have to go on exceedingly long for them to hear it in theory.

So, I would say based on these facts it is very plausible although somewhat difficult unless you have something like an amplifier like a speaker or something like that. Also, humans might be able to hear it if they are really close it. Some humans can hear higher than others.So, like with some clocks to everyone but a small few they are completely silent but to others they have a horribly high-pitched sound that the dog can also hear. That would also have to be considered.

# Not completely silent in the human audible range, no.

The best you can achieve is a grid of very small, millimeter-range steel or aluminum tympani, each with a steel needle in front, all the needles attached to a padded paddle. Instead of the tympani you can adapt @DarrelHoffman's answer and use tuning forks, which would need even simpler technology.

Hit the paddle with a drumstick, the needles hit the tympani and get a supersonic fundamental in the tens of kHz range. You need to fiddle with the tympani spacing, but it would work.

Problem is, the whole assembly would also inevitably vibrate in the audible range, and have audible harmonics.

Such a thing was once a product: the Zenith "Space Command" television remote control. It made ultrasonic pulses by hammering aluminum rods. It wasn't perfectly silent to humans, the hammer made a little click, but it was close.

One of the earliest ultrasonic transducers -- patented by Polaroid as a rangefinder in their cameras -- is essentially a drum.

The front face of the transducer is a sheet of gold foil (the drumhead). Behind it is a metal plate. Placing a voltage (typically 100 to 200 V) between the foil and the plate causes the foil to be attracted or repelled, moving the foil "drumhead", producing an ultrasonic pulse.

Any returning ultrasonic sound vibrates the foil. If charge is left on the foil, it acts as a variable capacitor, and the vibrations change the voltage across the device. Thus, the same device acts as transmitter and receiver. Your application only needs to be used as a transmitter.

They are still available for purchase today, even though smaller and better transducers are more common.