The human ear reacts to acoustic waves between 20 and 20,000 oscillations per second. While wave frequencies outside of this narrow band certainly exist, they are entirely outside the scope of human experience. Our senses have been honed over millennia to match the unique needs and interests of human beings—and that has required both a sharpening of senses as well as a narrowing of focus, in which our senses privilege what has supported survival in the past and shut out most everything else.
We have all become so conditioned by our culture to think that there is an external reality, “out there” and independent of our own observation, that many times we are inclined to forget how a large component of our perception originates from our own neurological wiring. We open our eyes and see a breathtaking array of colors, but these colors aren’t “out there” in the world at all; they are our brain’s way of coding for three different ranges of light frequencies perceived by the retina. Through echolocation (the kind of bio-Sonar used by bats and a few other mammals), an organism is able to develop a remarkably precise and well-populated map of its surroundings. But knowing the map of the territory is not the same as knowing the actual territory; we know only our own knowledge of the world outside ourselves, never the world itself. Our apprehension of the external world remains indirect—an inference based on our sensations and wiring.
It’s truly startling to imagine all the sonic data that our ears are missing. To begin with, our ears miss almost all of the ultrasonic squeaks used by bats in echolocation, despite these squeaks being quite loud—about the volume of a fire alarm, if we could hear them. Other animals (such as elephants) likewise employ low frequency “infrasound” for long-distance communication. We humans live our lives within a narrow band of sonic possibility, and to us it is everything. Until the last few hundred years, we weren’t even aware of these sounds lying beyond our perceptions.
It’s reasonable to assume that the music created by human beings also reflects, among other qualities, the particular possibilities and quirks of our own human experience of hearing—not only a predilection for the audible range of sound, but also for timbres and gestures derived from our earliest experiences in the world. There’s a part of me that is frustrated—disturbed, even—that I am stuck in a body that can never hope to perceive the totality of wonderful sounds that surround us each day. But there is also a part of me that cherishes these limitations, which are an emblem of our own humanness. Given the relatively few sounds that are audible to our species—in a range somewhere between the rumblings of elephants and the ultrasonic soundings of bats—we have managed to cultivate traditions and individual works that reveal much wider universes of feeling and expression.