The Biology of Sound

The human body is designed to be exquisitely sensitive to sound. In utero, our ability to hear develops by about eighteen weeks, making it one of the earliest senses to develop. By the end of the second trimester, research has shown that a fetus responds specifically to the sound of a mother’s voice & once out in the world, babies demonstrate a continued preference for the maternal tone. Doctors and hospice workers speculate that in the final moments of life, senses depart one at a time with hearing being the last to go which is why we’re advised to keep talking to our loved ones all the way through the end, even after it seems they are no longer cognizant. Hearing is, in this way one of our first and last modes of connection. Though the sound that we imagine in these scenarios is something like the voices of music, from a pure physics perspective, sound is silent. When we experience sound what is actually happening is vibrations are passing through matter be it gas, or fluid in the form of waves. These longitudinal waves move continually compressing and decompressing. Think of it like a Slinky stretched between two two people. If one person gives her end a push the Slinky ripples forward until it reaches the other person, then bounces back, continuing on and on. This compressing motion also determines the speed at which sound will travel. It takes longer for the sound waves to move to move through a less dense medium. like air, because the molecules are farther apart whereas in the case of water, they are closer together and more quickly transmit the vibrational energy from one particle to the next accelerating the speed at which the sound wave travels.

Vibrations transmitted as sound are measured in hertz which captures the frequency with which vibrations occur every second. The middle C note on a piano, for example is 262 Hz meaning that there are 262 vibrations every second when that note is struck. By contrast the fundamental frequency of a typical adult female voice the lulling melody that we attune ourselves to in the womb is 165 to 255 Hz, whereas a typical male voice is 85 to 180 Hz.

It’s astounding that we are actually able to hear the human voice at all when you consider how this happens. Our ears are an evolutionary adaption that makes it possible for us to receive information from one person who creates a pattern of pressure waves from the lungs that vibrate the vocal cords that then produce sounds into meaningful speech. In order for these sound waves to make sense we must transform sound waves into electrical impulses our brains can interpret. Once sounds pass your eardrums, these vibrations are sent to the middle ear, where there are three tiny bones, the smallest that exist in the body called ossicles. These bones form a chain from the eardrum to the inner ear that transmits these sound waves to the cochlea, a snail-shaped structure filled with fluid and “hair cells”, which are the sensory receptors of both the auditory and vestibular systems. When our ossicles move, the cochlear fluid begins to vibrate, causing the hair cells to shift as well. Different hair cells respond to different speeds of sound waves. Some move in response to higher-pitched frequencies, such as a baby crying, while others respond to lower-pitched similarly to a dog barking. The movement of these hair cells transforms the vibrations into electrical signals that travel through the auditory nerve a bundle of nerve fibers running from the inner ear to the brain where the information is decoded. Meanwhile, the auditory system also enhances useful information and reduces any distracting information from the various vibrations translating as sound from the world at large. Once the brain has finished deciphering this code, within about one-eighth of a second, these vibrations become intelligible language while also indicating where the sound came from and in what particular tone of voice. This is what happens every single time you hear a sound. In addition to this complex transaction, vibrations can travel through our skin as well as the fluid and bones within us just as they do through air making our entire bodies strikingly receptive to sound vibrations.

In addition to this complex transaction, we are able to ’hear’ pressure waves through the water that makes up roughly seventy percent of our body. And because water is less compressible than air, it conducts sound four to five times faster in our bodies. Lastly sound can also be transported through our bones. In fact our bodies are so conductive that physicians can use tuning forks to determine whether a patient has a bone fracture. A clear tone indicates an uninjured bone, whereas if the sound is diminished or absent, it indicates an interruption in the sound waves and the presence of a fracture is made known. Similarly, neurologists perform something called a Rinner test, which compares what we hear by air through the ear canal and eardrum to bone conduction through the mastoid bone to evaluate hearing loss.

There are also frequencies that are either too high or too low for the human ear to perceive, but are registered as vibrations through our nervous system. Though these vibrations are silent to us, they are still considered a form of sound, ranging from anything below 20Hz, which are infrasonic frequencies, to above 20,000Hz, which are ultrasonic frequencies. And over the course of the last sixty years or so, these inaudible frequencies have become valuable mechanisms within the Western medical world.

Sound

The simplest and most basic way to enhance a mantra practice is to focus on the sound of your own chanting. As I have explored mantra meditation has many benefits, including overriding thought patterns that have a harmful effect on our psychology and physiology. Everyone has maladaptive or ruminative thought patterns, by chanting, we can break up this unconscious dialogue. On a more profound level, the sounds themselves connect us to our true nature by attuning us to our true nature by attuning us to primordial vibrations.

Conclusion

Once you feel comfortable with your meditation practice, it is helpful to establish an intention or goal for your chanting practice. In Sanskrit, this is known as Sankalpa which is an intention that balances the desires of the soul with the practicality of human needs. It is generally a short, positive affirmation that focuses on a specific goal to work toward, such as “I will honor my body” or “I will uphold truthfulness in my life” or “I will be compassionate toward myself and others.” It can be called upon to reinforce your true beliefs and guide the choices you make in life.

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