Sound is a wave which is created by vibrating objects and propagated through a medium from one location to another. A wave can be described as a disturbance that travels through a medium, transporting energy from one location to another location. The medium is simply the material through which the disturbance is moving; it can be thought of as a series of interacting particles. Typically, this medium is air; though it could be any material such as water or steel. The medium is simply a series of interconnected and interacting particles. The vibr
ating object which creates the disturbance could be the vocal chords of a person, the vibrating string and sound board of a guitar or violin, the vibrating tines of a tuning fork, or the vibrating diaphragm of a radio speaker.
While we live with sound in our everyday lives and are quite familiar with it, it remains something seemingly intangible. The sound waves are invisible as they pass through the air, and the only part of it we can see is the source.
Or is it? Cymatics, the study of wavephenomena, focuses largely on the physical patterns produced through the interaction of sound waves in a medium. The waves through a physical, fluid medium can create a clear visual representation of the forces at work. The most potent demonstrations of this involve a fluid (which could be sand or a fine powder, along with liquids and solutions) spread onto a vibrating surface that produces a sound. As the waves pass through the fluid, it comes alive on the surface, reacting in a myriad of different forms. Sand often forms geometric ridges that follow the direction of the sound waves. A droplet of dye in water will form swirls that change with the sound frequency. My personal favorite version of this pheno
menon is cornstarch solution on a speaker. Being a non-Newtonian fluid, the cornstarch hardens as pressure is applied to it, and softens and pressure is released. So as the surface presses against the solution and pulls away, globules and mounds build up, that seem to reach upward and peel off the surface like some amoebic intelligence. The effects are truly startling.
Another way of visualizing sound is the oscilloscope: a type of electronic test equipment that allow signal voltages to be viewed, usually as a two-dimensional graph of one or more electrical potential differences (vertical axis) plotted as a function of time or of some other voltage (horizontal axis). These are most famously used in heart monitors, but a more artistic application is to free up the green line from its strict axial limitations, so that it can move every which way in response to different pitches. The results can be visually striking.
While the previously mentioned methods are excellent for showing the physical disturbance caused by sound, their representation of pitch is imprecise and obscure. The clearest way for one to examine the various pitches in a sound is an audio spectrograph. This digital imagery shows the pitch on the y axis, and time on the x. As a sound plays through the spectrograph, the viewer sees a landscape of glowing textures and swirls, a visual analogue that perfectly represents what one is hearing. As can be seen in the image, this process does not only go one way. Programs exist now that allow audio technicians to "draw" images into a spectrograph, and convert them into sound. The demonic visage in the picture is Richard James of the one-man-band Aphex Twin. He is a Scottish electronic musician who famously uses his face in unexpected and unsettling ways.
The ties between sight and sound can be taken much further, and represented more directly, than the iTunes visualizer. Since a sound wave becomes an onscreen performer in Disney's Fantasia who displays various instruments in terms of abstract visuals that mimic the pitch and sharpness, artists have toyed with the relationship between sight and sound. Digital technology has opened the door to whole new ways to explore such ideas.
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