Sound is fundamental to who we are as beings.
Unlike the vast majority of the universe, earth has an atmosphere. Unlike the vast majority of those atmospheres in the universe, the one on earth is both dense and replete with oxygen.
Fortunately for we humans, this greatly assists us in the subtle art of not dying.
In addition to keeping humans and other animals alive, the particles in our atmosphere allow for the transmission of sound. Like ripples in a pond, pressure waves emanate from sound sources such as plucked strings, vibrating voice-boxes, percussed drums, or obnoxious weed-eater. These waves impact the ear-drum periodically, and the rate at which they do so, otherwise known as the “frequency”, is perceived as the tone of the pitch.
You’ve probably noticed that the low-frequency “woof” of a German Sheppard is quite different sounding from the high-frequency “yip” of a chihuahua. This phenomenon is due to the size difference in the chest cavities, larynx, and skulls of the respective dogs.
One can even think of the ribs of a larger animal like larger, and thus lower-pitched, keys on a xylophone.
With the speed of sound constant, sound waves can traverse back-and-forth, from rib to rib, many more times per second in a tiny, yappy chest than in a thumpy, “good-doggo” chest, many times greater across. Observing this phenomenon, one can develop a knack for determining the approximate size of a dog based solely on the frequency of their bark.
why can a Tuvan throat singer from Mongolia sing many notes lower than a bass singer in the opera? The nature of the singing allows for the much larger chest (rather than the skull) to serve as the primary source of resonance; as above, a larger vibrating object will generate a lower note than a smaller one.
Ever wonder why a smartphone, despite benefiting from some of the best sound-engineering in the world, cannot replicate the presence of sound systems at music festivals? Once again, like the chihuahua’s chest, short-end of the xylophone, and the vocalist’s small skull-to-chest ratio, the smartphone is physically limited by its tiny size to a range of frequencies well above the booming waves possible with a speaker the size of Luxembourg.
Next time you hear a winged insect buzzing by, a rock tumbling down a hill, or an alien spacecraft landing at your barbeque, consider imagining the audible tone getting higher as the rate of vibration increases, or as the size of the object decreases.
In the world of digital sound, all bets are off… but that’s a topic for another article.