Sitting in my office writing and listening to jazz is a sublime experience. I consider how sweet it is to hear the rich sounds and ponder what it tells us about God and His nature. Exactly what is sound? You may take for granted the complicated process involved with hearing, which happens when vibrating air molecules move our tympanic membrane (our eardrum). Our brains especially like it when those air molecules arrive in harmonically and geometrically related waves. You may not like math, but your brain likes order and mathematical relationship in sound waves. Music can make us feel happy or sad, energized or sleepy. The joy of music is the connection between our ears, brain and emotions. If we were robots, our ears would be the sensors, our brain the computer, and emotion would be outputs from the algorithmic processing on that computer. Many engineered systems mimic what the human body does so well but no machine will ever get goosebumps during O Fortuna from Carmina Burana or feel sad listening to Samuel Barber’s Adagio for Strings. In A Beautiful Day in the Neighborhood, Mr. Rogers is shown striking all the lowest keys on the piano when he’s angry. Music can be cathartic.
We don’t have to think about a song to know if we like it – it’s visceral. Art is like that. We must consciously process numbers to balance our checkbook or consider the terms of a mortgage but to appreciate music requires no analysis at all. Music is the window to the soul, capable of moving us to tears as we give ourselves over to worship – and the Bible speaks of music often. Music can be rebellious or mellow, calming or uplifting. It is no wonder God tells us to sing songs of praise to Him because the entire book of Psalms is meant to be sung out loud. Let’s dig into what sound actually is and what it might tell us about God’s nature.
Sound is just the human perception of air molecules vibrating within a specific range of frequencies from about 20 Hertz (Hz) to 15 kHz (20 kHz when you’re very young). Your dog can hear above 20 kHz, like a dog whistle, but you can’t because your sensor is inferior to your dog’s. But sound is rich and nuanced, how can it be as simple as vibrating air molecules? Why is it that a flute sounds smooth and mellow but a clarinet is raspy? How are we able to distinguish the oboe from the saxophone? It’s the unique way each instrument issues forth waves of air molecules that makes the sound special. It’s subtle yet when you hear an orchestra your brain can immediately distinguish the oboe from the clarinet, or which of your children’s voices it is hearing. The processes involved with perceiving sound are fascinating and surprisingly complex. It involves hydraulics, Fourier Transforms, and resonance.
In order to hear, your eardrum needs to move. Air and water can do that because their molecules will vibrate under pressure and what happens next is fascinating. The energy exerting pressure on your eardrum is transferred to tiny little bones deep within your ears called ossicles that push fluid over a very small area, increasing pressure in your ear. Pressure increases as the surface area decreases, which is necessary since it’s more difficult to move fluid than air and this pressure increase exploits a principle called hydraulic multiplication. The pressure waves in the fluid are next transferred into nerve impulses when they pass over the basilar membrane which has thousands of little fibers of various lengths, each designed to be sensitive to different frequencies of sound. When these little hairs are moved, they send electrical impulses through the cochlear nerve to the cerebral cortex in the brain (your computer).
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So why does a flute sound different than a clarinet? Though they each play the same note, they shape the waves of air molecules differently. Let’s say that note is a middle C, pressure waves 3.8 milliseconds apart move through the air, vibrating your eardrums 262 times a second, or 262 Hertz (Hz). The waves of air pass over the fine hairs deep in your ear and that stimulates your brain. But instruments never play just a pure tone, never just the 262 Hz fundamental. They also produce sounds at twice, three times, and even higher multiples of that frequency. These are called harmonics of the fundamental. The relative amplitude (volume) of each harmonic changes how the same note from different instruments sounds in your brain. These harmonics produce the timbre of instruments you know so well. Each instrument is crafted to produce a rich timbre. The sounds produced tend to be those that are sustained due to resonance which I wrote about previously here.
A few hundred years ago, a French mathematician, named Joseph Fourier, devised a way to decompose signals into a sum of harmonically related trigonometric functions. A famous mathematical transform, aptly called the Fourier Transform, can be used to convert any sound waveform into fundamentals and their harmonics and the levels of those harmonics determines the timbre of a voice, instrument, or pretty much anything. The human ear essentially computes the Fourier Transform of the incoming sound waves so we can decode the rich combination of pitches and discern the clarinet from the flute, and the oboe from the bassoon. In digitally synthesized music, tones are generated electronically and assembled to mimic real acoustic instruments. Our ears reverse this process by receiving a composite sound waveform and sorting out the different frequencies and their harmonics. Our ability to do that enables us to know the middle C we just heard was from a piano and not a flute. Your eyes can’t do that! When you see white light, it has all the colors of the rainbow, but unless they are broken out using a prism, you only see the additive result of those different wavelengths – white light. Your ears can separate the blue, green, and red!
God gave us the gift of hearing to let us experience more of Him! As we engage our senses in experiencing Him we enjoy Him more fully. How could we spread the gospel without sound? So faith comes from hearing, that is, hearing the Good News about Christ. – Romans 10:17
God is omniscient – He can hear all acoustic frequencies and see all electromagnetic frequencies. Our audible range of hearing is a whisper of His capability, shared with us by His grace. If you’ve ever suffered temporary hearing loss, remember how glad you felt when it was restored! Imagine if we could hear beyond the normal range – what feelings might those new sounds evoke? God also wants us to hear each other speaking and singing and to enjoy the sounds of creation like crashing ocean waves and birds chirping on a summer day. All of these are His gifts to us, so he who has ears to hear, let him hear!