The sound of color

by Aaron N. Kelley

When I was researching biofeedback , I found people had been studying the effects of sound and light on states of consciousness for many years. Brainwave synchronization is now a common practice. It seems everything has resonance, and things will vibrate in tune with external stimuli. Entrainment of the brain’s states using binaural beats are reproduceable with simple equipment . An EEG can be used to watch brain activity. Using sound and light for healing or changing states of consciousness seems perfectly logical to me, so if you have hang-ups in that area of thought, don't bother reading any further. My ideas are based on foundations like these.

Using wavelength as a common measurement.

Light and sound have measurable wavelengths. This is the objective principal that I based the idea that binaural beats, certain tones, and color have a harmonic relationship to each other. Normally, what is meant by harmonics is the octave relationship of tones as they sound "the same note" higher or lower. I have a different way of looking at harmonics. Because of this perspective, they might not even be harmonics at all, but a system of using a common denominator, which is wavelength.

In acoustics and telecommunication, the harmonic of a wave is a component frequency of the signal that is an integer multiple of the fundamental frequency. For a sine wave, it is an integer multiple of the frequency of the wave. For example, if the frequency is f, the harmonics have frequency 2f, 3f, 4f, etc. So, "the same note" is higher or lower than the fundamental but still related by frequency or octaves. Taking this definition of a harmonic to the extreme would yield sounds that are too high or low to hear, but still a harmonic of the fundamental. One could say that these frequencies are harmonics or have a harmonic relationship.

We can measure both sound and light in meters and nanometers. Sound's wavelength can be expressed in terms of centimeters and light typically is expressed in nanometers. These measurements are derived from the speed of the energy (for sound I used 345 meters/sec, and for light 300 million meters/sec) and frequency of one cycle of the waveform. So if a sound is 1hz (or one cycle per second) at 345 meters per second then the distance that one cycle of that waveform would travel would be 345 meters. Thats pretty long, and 1hz is far below human hearing but the number 1 is an easy way to show the translation process. What I want is, sounds that we can hear (20hz-20khz) translated (from hz to meters) into harmonic equavalents extremely high up, which could be colors. Not all sounds will have harmonic equavalents in the visible spectrum of light, and not all colors will be within the range of human hearing.

First I had to choose a constant speed for sound since sound's speed varies with air pressure and temperature. I chose 70 degrees at sea level. Light's speed is relatively constant (let's not get into this right now) so I'm using two givens to start with here: Sound travels at 345 m/s and light travels at 300 million m/s @ sea level @ 70 degrees. My charts are based on controlled environments where I have less variables to deal with.

Finding the numbers

We percieve sound's frequency

We don't percieve the wavelengths of sound when we distinguish pitch (if we do it's not consciously). Our brains interpret the frequency. I started with the measurments of different frequencies of light (color), and translated the "octaves" of wavelength harmonics down into our range of hearing. The other way would be to start with the frequencies of sounds and translate upwards untill they match with color wavelengths.

Even temparament was started in order to be able to play in many different keys without having to retune the instrument every time. This may sound pleasant to our ears, but this is not the true relationship that sounds have in a strict physical sense. We scoot the notes around so that they make sense, but I wanted to make the point that this is just a system of dividing up a scale into even portions to make certian relationships happen that we enjoy. I feel that I owe a lot to even temperament, but the key to my experiments is not necessarily to make something beautiful. Although, I would like to eventually be able to use the wavelength harmonics to make art if possible.

I took the conventional measurments (in nanometers) of six colors and in a wavelength calculator, input the length of the center point of, for example, a very pure red (Colors cover a bandwidth and the center could be called the most pure). Red could then be said to have an approximate wavelength of 650nm. This wavelength is translated to 527,692,307.6923hz (1hz = 1 cycle per second). This is obviously very far out of our range of hearing. If one applies the principal of wavelength harmonics to that sound, then you can find the lower octaves of that color's note that fall into the range of human hearing. I divided the frequency by 2 untill within the range of normal hearing. The table below has the audible frequencies. I put the sounds in this .zip

Red @ 650nm	16103.8912	8051.9456	4025.9728	2012.9864	1006.4932	503.2466	251.6233	62.9058	31.4259	15.7264	~
Orange @ 590nm	17741.5750	8870.7875	4435.3937	2217.6968	1108.8484	554.4242	277.2121	138.6060	69.3030	34.6515	17.3257
Yellow @ 570nm	18364.0864	9182.0432	4591.0216	2295.5108	1147.7554	573.8777	286.9388	143.4694	71.7347	35.8673	17.9336
Green @ 510nm	20524.5672	10262.2836	5131.1418	2565.5709	1282.7854	641.3927	320.6963	160.3481	80.1740	40.0870	20.0435
Blue @ 475nm	22036.9037	11018.4518	5509.2259	2754.6129	1377.3064	688.6532	344.3266	172.1633	86.0816	43.0408	21.5204
Violet @ 400nm	26138.8232	13084.4116	6542.2058	3271.1029	1635.5514	817.7757	408.8878	204.4439	102.2219	51.1109	25.5554

Click on the colored boxes below to see my first tables: