Sometime in the early 2000s, I read about Alexander Scriabin’s idea of the clavier à lumières: a theoretical keyboard instrument that shot beams of colored light instead of musical tones, an image that never really left me and for some reason I always found both beautiful and slightly terrifying.
My recent experiments with lasers are centered around the concept of controlling a precisely-tuned high-powered laser with pure audio signals, using custom made hardware and Max/MSP patches, and investigating the resultant 1:1 relationship between image and sound.
My first introduction to lasers was a musical problem. One of the largest struggles of musicians across all time-periods and genres is also microscopic in nature: sweating that one millisecond for rhythm, and fractions of a single hertz for tuning.
Especially in the extreme reaches of experimental microtonal music, like in my work with the JACK Quartet, the difference of 1/10th of a half-step can feel massive, yet simultaneously borderline-imperceptible. How can we learn to more effectively zoom our ears in to fully perceive these subtleties?
In the last few years, I have been interested in how visual stimuli can help our ears perceive absurdly subtle sonic detail that it might otherwise miss. This was my initial motivation for using sound to control the movement of a laser beam: the resultant image is a clear and vivid description of microscopic sonic details.
Sometime in the 19th century, physicist Jules Antoine Lissajous reflected a light beam off two perpendicular mirrors attached to vibrating tuning forks, and observed that the resulting figures were precise parametric curves describing the complex harmonic motion between those two tuning forks. If one fork is vibrating at 300hz and the other at 200hz, the resultant light pattern is a simple and elegant visualization of that 3:2 harmonic relationship. On the exterior edge of the pattern, one can see 2 “lobes” along the horizontal axis, and 3 along the vertical axis.
If that relationship is exactly in tune, the pattern of light appears to remain stationary. But if it is out of tune by even less than 0.1hz, the pattern begins to shift and even almost appears to rotate as the sound waves constructively and de-constructively interfere with each other.
In music, this is what is called “beating”, and is how musicians tell by ear if something is precisely tuned to a simple, whole-number relationship. It is extremely difficult, however, to hear if something is out of tune by a tiny amount like 0.1hz (each beat lasting 10 seconds).
If those slightly beating frequencies were fed into a high-precision laser, however, this subtlety is immediately clear: the pattern would begin slowly moving in and out of phase, re-aligning every 0.1hz (10 seconds), affirming the small changes our ears are indeed hearing.
Apart from its use as a tool, the audio-driven laser is one of the more intense and powerfully expressive musical instruments I’ve personally used. It is almost disturbing in its ability to move between almost-subliminal subtlety for one moment, and then in the next, completely overwhelm one’s senses with speed, brightness, complexity, and an almost elemental rawness.
And unlike light from a screen or a projector, which to me is a rather one-dimensional flat image, one sees the full length of the beam. It travels very visibly through the three-dimensions of a physical space.
For me, that three-dimensionality speaks directly to the innately immersive quality of sound itself: waves propagating throughout a physical space in all three dimensions.