An Investigation Into the Relationship

Between Sound and Color

Joe Goldsmith

Introduction

This paper presents a short investigation into the concepts of sound and color. Is there a theoretical relationship between sound and color that explains the behavior of each and proves some objective correlations? The physical properties of both sound and light including concepts of blending and origin are discussed and then compared and contrasted. A brief history of related studies are also discussed with some examples of color and music wheels. Finally, the synesthetic experience of hearing colors is investigated.

Characteristics of Sound and Color

Sound is produced by a mechanical means. Sound travels in waves and exists only within a medium. Light also travels in a wavelike manner but light has electric and magnetic properties and accordingly it is an electromagnetic (EM) wave. Sound travels at 343 m/s in air and light travels through all mediums at almost 300,000,000 m/s. Everyone has heard that light travels faster than sound. In fact, light travels 1 million times faster than sound. One way to describe waves is according to the distance between each peak of the wave, just as in a wave at sea. This distance is called the wavelength and is measure in meters. Another way to describe waves is according to how many peaks pass through a point in one minute (how many waves crash upon the shore in a second?), and is labeled cycles per second of Hertz(Hz).

The electromagnetic spectrum is pictured in Figure 1. This spectrum shows all known types of EM waves. Visible light occupies a very small portion of the spectrum.

Figure 1. The Electromagnetic Spectrum

The range of wavelengths for visible light is between 400 nm and 700nm shown in Figure 2. One nanometer (nm) is a trillionth of a meter.
Visible light when broken up, forms the colors of the rainbow also shown in Figure 2.

Figure 2. The Visible Light Spectrum

Characteristics of Sound

Sound is also classified by wavelength, but keep in mind that sound is produced by mechanical means. Sound does not have the electrical and magnetic fields that visible light does.

Sound also travels much slower than does light. The audible sound spectrum consists of sounds between frequencies of 20 Hz and 20,000 Hz. These waves are very large and very slow compared to light waves. Sound waves are approximately 1,000,000,000,000 times larger than light waves.

Sound Blending/Color Blending

Sound and color (light) both have a wavelike character but are very different. They are vastly different in both size and speed. Both color and sound cover a range of wavelengths, but color is not restricted to a single wavelength. The pitch of the note A has a frequency of 440 Hz. If notes were sounded around the A but of slightly smaller or greater frequencies, the result would produce pulses in the sound and an unclear tone. As the size of difference in frequency is increased, the sound would be dissonant and very unpleasant to listen to for an extended period of time. Sound is not continuous in this sense. Color on the other hand is continuous. If a red were produced at one particular wavelength of light and slightly different wavelengths added into the color, the appearance would change subtly and the eye would start to notice the red deepening or lightening depending upon the color being added. There is not a dissonance in color blending as there is in sound blending of similar notes. This is because of the continuous nature of light, and the step nature of sound.

Not all sound blending is dissonant. There are certain combinations of sound intervals that produce very pleasing relationships. These instances comprise the relationship between harmony and melody. When two harmonious notes are sounded, each note can be heard and both sound complementary to the other. When color is blended, each color loses its individuality and a new color results. Two colors placed next to each other would have the same effect as two notes. The observer could see both colors and comment on the relationship between them. Perhaps an untrained ear could not distinguish between two notes, but no amount of eye training will free the eye to separate blue and yellow from green.

Sources of Color and Sound

Sound and color also have different origins. Sound emanates from an object that acts mechanically to produce the sound. The object produces the sound. A large rock thrown into water will create a splash. Shattering glass creates quite a pleasant sound to some people. The sound comes from the object. On the other hand, an object appears to be colored because of the interaction of white light with the object. White light strikes an object, the object absorbs certain parts of the light, one might say it absorbs all colors but blue, and the light leaving the object would then contain whatever color is left, or blue for the example. In a sense the real color of a blue book is a combination of every color but blue. This is not accurate because the object itself it not colored. Color is perceived as the reaction of light with an object.

History of the Studies

Plato pondered the idea of eight concentric circles each with a distinctive color and tone. The eighth note was a repeat of the first note and all the notes sounded together produced what he termed as the "music of the spheres". This was quite an advanced idea for a time when there were no prisms and rainbows were not frequently seen. Aristotle suggested the first color-music formula. He had no conception of the color spectrum so he invented his own spectrum with black and white as the ends and several colors in the middle including red and purple. Aristotle assigned colors to musical tones according to how the colors and tones blended. Much of this early work on color and music was purely speculative.

Sir Isaac Newton observed the colors of the rainbow via a prism in the 17^th century. He ascribed the acronym ROYGBIV to the seven colors. Niels Hutchinson writes that Newton split the rainbow into seven sections intentionally to mirror the seven notes of the musical scale. With a good prism, seven colors are clearly visible and so the necessary relationship between the seven colors and seven principle notes should be challenged. This will be addressed shortly. Newton also attempted to create a music-color wheel, shown in Figure 3.

Figure 3. Newton’s Music-Color Wheel

Each wedge is assigned a color and the note preceding each wedge corresponds to the color. The design of this wheel was entirely arbitrary. Another arbitrary formation of a color wheel can be seen in Figure 4. Each color is assigned to a key on the piano. This coordination was developed by Dominic De Clario and used in a presentation of light and sound in 1995. All of the colors in the show were coordinated to the particular key of the music and the particular notes being played.

Figure 4. Music-Color Assignment According to Dominic De Clario

Declario wanted to have white light as part of the color selection and he chose to add it as one of the key colors. White light is the sum of all of the visible colors. To replace indigo with violet demonstrates how this music-color scheme is arbitrary and unscientific. It is particularly easy to coordinate seven colors to seven notes. A relationship is not established between sound and color because there are equal numbers of each. In fact, the seven whole tones in the western system of notation is also arbitrary. There are a total of 12 notes in the western scale. Indian musicians use a system of quarter tones for a total of 22 notes. The western system of music has become a standard largely because it is easier to use. It works, but just because it is easier does not make it the standard. A popular way of dividing up an octave of notes is with seven divisions. It is not the only way and so the seemingly magical relationship between seven colors and seven notes probably is not so magical. It probably came around in a deductive application of the number seven instead of objective study of the sound and color.

On the website The Metaphysics of Music and Harmony another example of the relationship between color and music is displayed. In Figure 5, the 12 tones are arranged around a wheel. Figure 6. has the seven colors arranged around a wheel. Both charts show a one third division. For the tones the relationship shown is the notes C and E. These two notes create a harmonious interval. The colors shown at the same distance are red and yellow and are also harmonious colors. The author has taken the music and color wheels an extra step in pointing out the relationships.

The author also explains out that opposite colors yellow and purple and opposite notes C and F# are dissonant and unharmonious. These are mainly opinions. The C and F# relationship, the tritone, is a staple of jazz and western music. The disharmony of yellow and purple may be quite pleasant to some people. It is a rather common color combination. These two wheels offer some insight into sound consonance and dissonance but they are not firmly rooted in a theoretical background. They do offer some insight into music color relationships.

Synesthesia

The word synesthesia comes from the Greek words syn meaning together, and aesthesis meaning perception. Synesthesia literally means cross-sensing, one of the senses being triggered by another sense. A synesthete might hear colors, taste sounds, see smells or any combination of the senses. Does this phenomenon offer any insight into the relationship between sound and color, particularly from individuals who hear colors? There has been significant study of the phenomenon of synesthesia and some light has been brought to the subject.

Females and left-handed people are typically synesthetic. Ratios of women to men synesthetes have been reported at 3/1 and even as high as 8/1. A typical feature of synesthesia is that the particular sensations, the color blue associated the pitch C, are consistently experienced. Whatever sensations the subject experiences are always the same sensations, the same tastes, sights, sounds, smells and touches. These sensations frequently enhance memory and are directly combined with the person’s memory functions. Synesthesia is reported to run in families. It is not an abnormal phenomenon but it happens in low frequency. A current understanding of synesthesia is that it is a premature experience of the perception like tapping into a signal and viewing it before it reaches the television screen.

Synesthesia has been known to medicine for 300 years. Traditional ideas about the experience have consisted of a ‘crossed-wire’ explanation. Somehow the sensory information is switching to a new channel and showing up in a different sense. Many studies are underway today and much information has been gathered about synesthesia. Richard Cytowic diagnoses five characteristics of synesthesia on his article Synesthesia: Phenomenology and Neuropsychology. The five characteristics are 1) involuntary experience 2) projection of sensations 3) sensations are durable and generic 4) sensations are memorable 5) sensations are emotional and poetic.

The first characteristic is that the experiences are involuntary and passive. The subject does not control them but experiences them as they happen. The second characteristic means that the experiences of synesthesia do not occur inside one’s mind, moreover they are perceived to take place within the subject’s personal space. The third characteristic of synesthesia is that the sensations are generic and durable. Cytowic means that the experiences remain the same for any particular person. The experiences are generic in the opposite understanding of an elaborate memory that might be awakened by a smell or a sound. These sensations are simple colors, tastes, textures etc. They are not elaborate in nature. The memorable quality of the synesthetic experiences explains why synesthetes usually have good memory. The experiences are tied into the person’s memory. Cytowic means by the last characteristic that the experiences are real for the subject. They are tangible and real to the mind of the perceiver.

Hearing colors is quite a common experience among synesthetes. The perceptions of colors associated with particular sounds has been found to be consistent among individuals but not between individuals but no common set of color and sound associations exist between individual synesthetes. Synesthesia is a personal experience and the details of the perceptions are completely subjective. This disgruntles the effort to use a common experience of hearing colors to provide objective data to explain a deeper relationship between sound and color. If large groups of people would hear the color red when a D was played, or the color green when the notes F and C were played, there would be insight into a physical and a psycho-perceptive understanding of how sound and color are connected. Future studies of synesthesia may prove otherwise, but for now no conclusions can be drawn.

Summary

Long has the question been pondered of whether sound and color have some profound mathematical or physical connection that explains related attributes of origin, blending, contrasting or consonance and dissonance. Synesthesia, although proves a relation between sound and color, is rooted in subjective experience and cannot give light to physical relation. The sciences will continue to elaborate upon this field as studies continue and data is gathered.

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Synesthesia http://www.vislab.usyd.edu.au/user/alyons/synaesthesia.html http://wabakimi.carleton.ca/~sscott2/sam/Synaesthesia.html http://www.seattlesatellite.com/tom/synesthesia.html http://www.slip.net/~bindu/index.htm http://www.qnet.com/~moonbase/cmsyn.htm http://ourworld.compuserve.com/homepages/Peter_Meijer/javoice.htm (seeing with your ears) http://dir.lycos.com/Science/Social_Sciences/Psychology/Synaesthesia/

Sound and the Ear http://www.digital-recordings.com/audiocd/journey.html#content http://www.silcom.com/~aludwig/EARS.htm http://www.glenbrook.k12.il.us/gbssci/phys/Class/sound/u11l2d.html http://online.anu.edu.au/ITA/ACAT/drw/PPofM/INDEX.html