Sound is a concept that describes the brain’s perception and interpretation of a physical auditory stimulus.
The distinction must be made between the physical phenomenon of sound and the perception of sound.
For as long as I can remember, sound has been a fascinating ball of energy to me. Sound or vibrations permeate through everything, from the hundreds of birds chirping in the morning to the rumbling earth underneath us; all vibrations give us a different sense of emotion. Neuroscientist Seth Horowitz, Author of the book The Universal Sense: How Hearing Shapes The Mind is especially interested in the way all these vibrations have helped shape the evolutions of the human brain.
“Vibration sensitivity is found in even the most primitive life forms,” Horowitz says — even bacteria. “It’s so critical to your environment, knowing that something else is moving near you, whether it’s a predator or its food. Everywhere you go, there is vibration, and it tells you something.” From tiny insects to larger mammals, we all need sound to function.
Depending on how well the sound reflects, our brain interprets the distance and helps us localize the sound and we have evolved to be exquisitely sensitive to it.“You hear anywhere from 20 to 100 times faster than you see so that everything that you perceive with your ears is colouring every other perception you have, and every conscious thought you have.” Sound, he says, “gets in so fast that it modifies all the other input and sets the stage for it.”
It can do that because the brain’s auditory circuitry is less widely distributed than the visual system. The circuitry for vision “makes the map of the New York subway look simple,” says Horowitz, whereas sound signals don’t have as far to travel in the brain.
And sound gets routed quickly to parts of the brain that deal with very basic functions — “pre-cortical areas,” Horowitz says — that are not part of the wiring for conscious thinking. These are places where emotions are generated.“We’re emotional creatures, and emotions are evolutionary ‘fast responses’ — things you don’t have to think about. That speediness pays dividends in the survival department: You hear a loud sound?” he says. “Get ready to run from it.” Emotions are rapid delivery systems in the brain and sound drives emotions.
It’s fascinating that there is little awareness around the depths and interplay between sound, hearing and emotion. I wonder if, with greater education around these ideas, humans would more often harness the therapeutic power of sound in order to sway emotion.
As I mentioned previously, this project will explain the ABC’s of sound. With that in mind, this first part post would probably be the “A” that describes all the fundamentals.
There is geometry in the humming of the strings
… there is music in the spacing of the spheres.
Did you know that in the sixth century, B.C, the great Pythagoras was one of the first to make discoveries regarding sound? He noted the relationship between the length of a vibrating string and the tone it produces — what is now known as the first law of strings. Pythagoras believed that the celestial bodies around us emitted a form of music, a ‘hum’ based on their orbital revolution, and he called it the ‘Musica Universalis’ or ‘Music of the Spheres’.
Aristotle, Leonardo Da Vinci and Galileo have also made massive contributions to sound. Da Vinci discovered that sound travels in waves and Galileo discovered the properties of sound. He demonstrated that the frequency of sound waves determined the pitch. From then on all the experiments regarding sound began, and the world progressed in technology. In about 1640 a French mathematician named Marin Mersenne conducted experiments to determine the speed of sound in air, and a few years later a British scientist named Robert Boyle demonstrated that sound needed a medium to travel in to be heard. Sound had developed from survival to science and was becoming widely examined.
Today the advances in music technology are immense. There are acousticians that design concert halls, products that synchronise, distort, reverb and generate sound and technicians that curate festivals. There are audio engineers that make Justin Bieber’s music reach a million hits in an hour, an inconceivable feat.
Understanding the discoveries and Sound
Leonardo Da Vinci was once standing by a well and noticed a stone hit the water at the same moment that a bell went off in a nearby church tower. He noticed the stone caused circles until they spread and disappeared. By simultaneously concentrating on the circles in the water and the sound of the bell, he made the connection that led to his discovery that sound travels in waves. What this means is that sound is the movement of air and a pressure wave. It is the result of the back and forth movement of air particles the medium through which the sound wave is moving. When an object vibrates say a paper fan — the paper fan pushes together the air particles surrounding it, then pulls the air particles apart. The pushing of the air particles is called compression and the pulling, rarefaction.
For us to get a better understanding how sound works we use waveforms. Waveforms are graphical representations of sound and the wavelength of a wave is the distance between a point on one wave and the same point on the next wave. It is measured from the peak of one wave to the peak of the next wave.
Sound cannot travel through a vacuum. Hence, it is impossible to hear sound in space. Sound needs a medium to travel in; the medium can be air, water, wood, concrete, etc.
Here’s some fun trivia for you. The speed of sound changes with temperature, humidity and air pressure. The speed of sound is 344m/s on a normal 20-degree temperature. The speed of sound is greater in hot air than it is in cold air. This is due to the molecules of air moving faster.
Sound travels at different speed in different gases, the speed of sound in helium is 972m/s thus, giving us the ‘Donald Duck’ voice. Even if we happened to be on any other planet, we would sound totally different because of the atmosphere.
All life forms have an audible range of hearing. Human beings can hear from 20 Hz to 20 kHz, Dogs can detect from 50 Hz to 45 kHz while dolphins can detect up to 200 kHZ. Hz (Hertz) is a measurement for Frequency. Frequency refers to the number of repetitions (cycles) of the waves produced by the same source each second. A frequency of 500Hz indicates a wave is repeating one cycle 500 times per second.
Check how good your hearing is below.
Pitch is the perceptual property of frequency. The sensation of a frequency refers to the pitch of a sound. The higher the frequency of a waveform, the higher the pitch of the sound you hear.
I hope that you haven’t been jaded with this post. For the next part of this post click here. For a piece of beautiful music click here.
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