Surfing the Waves: Sound and Music
Dwan Dunning
Prepared for Dr. Neil
Marshall
SM 102 Development of
Scientific Thinking
This paper explores sound and music, attempting to present an understanding of music from both a scientist’s and a musician’s perspective. Included are sections on the nature of sound, sound waves, the human ear and brain, and an interview with a musician. The disparate approaches to an understanding of the subject are discussed, in respect to objectivity and creativity.
Surfing the
Waves: Sound and Music
The relationship between science and the arts has traditionally been uneasy; artists feel that scientists are akin to automatons, while scientists regard artists as illogical and unpredictable. However, a relationship certainly exists: specific to this paper, music could not be played or heard without physiology and acoustics.
Hermann Helmholtz, the nineteenth-century German physician and scientist, wrote in the preface to his classic book, On the Sensations of Tone (1877), that:
Those who prefer mechanical explanations express
their regret at my having left any room in this field
for the action of artistic invention and esthetic
inclination…other critics with more metaphysical
proclivities have rejected my Theory of Consonance,
and with it, as they imagine, my whole Theory of
Music, as “too coarsely mechanical.”
Helmholtz here succinctly sums up the basic differences in approach by musicians and scientists to the study of music and sound. Only by exploring both sides are we able to achieve a balance and breadth of knowledge.
The first question to be answered in the understanding of music and how we hear it is: “What is sound?” From a layman’s perspective, sound is anything we hear. More specific definitions (edited to include those which describe the subject of this paper), according to the American Heritage Dictionary (4th ed., 2000) are:
Sound
n.
1. a. Vibrations transmitted through an elastic solid or a liquid or gas, with frequencies in the approximate range of 20 to 20,000 hertz, capable of being detected by human organs of hearing.
b. Transmitted vibrations of any frequency.
c. The sensation stimulated in the organs of hearing by such vibrations in the air or other medium.
. d. Such sensations considered as a group.
e. The
distance over which something can be heard: within the
sound of my voice.
Helmholtz (1877) delineates a difference between sound and musical tone:
The first and principal difference between
various sounds experienced by our ear, is
that between noises and musical tones…Noises
and musical tones may certainly intermingle in
very various degrees, and pass insensibly into
one another, but their extremes are widely separated.
He goes on to describe the nature of the difference by stating that:
…generally, a noise is accompanied by a rapid
alternation of different kinds of sensations of sound…
rapid, irregular, but distinctly perceptible alternations
of various kinds of sounds, which crop up fitfully…
On the other hand, a musical tone strikes the ear as a
perfectly undisturbed, uniform sound which remains
unaltered as long as it exists, and it presents no
alternation of various kinds of constituents…To this
then corresponds a simple, regular kind of sensation,
whereas in a noise many various sensations of musical
tone are irregularly mixed up and as it were tumbled
about in confusion.
Harry F. Olson, formerly Staff Vice President of Acoustical and Electromechanical Research at RCA Laboratories, wrote in the 2nd edition of his book, Music, Physics and Engineering (1967):
Music is the art of producing pleasing, expressive,
or intelligible combinations of tones…The evolution
and production of combinations of tones by composers
and musicians, which have been accepted by the listeners
as pleasant and expressive, have gone on through all the
ages of man.
Olson (1967) also gives us two definitions of “sound,” along with a clarification:
Sound is an alteration in pressure, particle displacement,
or particle velocity which is propagated in an elastic medium,
or the superposition of such propagated alterations.
Sound is also the auditory sensation produced through the ear
by the alterations described above.
From these definitions it will be seen that sound is
produced when the air or other medium is set into
motion by any means whatsoever.
As both scientists, Helmholtz and Olson, claim that all music is sound (although all sound is not music), it is important to understand how sound travels to (and is received by) us.
When sound is produced, the air (or other medium, such as water) molecules are displaced, and form a pattern, or pulse, of atmospheric pressure. This pattern alternates between “condensation,” in which the pressure is higher than the normal undisturbed atmospheric pressure, and “rarefaction,” in which the pressure falls below the normal undisturbed atmospheric pressure (see fig. 1). This “sound wave” travels outward in all directions at the velocity of sound (1100 feet per second). The magnitude, or difference in pressure between normal undisturbed pressure, condensation, and rarefaction, diminishes in proportion to the distance from the point of production (Olson 1967). Any vibrating body in contact with the atmosphere will produce sound waves. It is important also to realize that the actual physical displacement of air (or water) molecules is very small in a normal sound wave in speech and music. For instance, in normal
conversational speech at a distance of ten feet from the speaker, the particle amplitude (which is the measurement of the physical displacement of the surrounding air molecules) is about one-millionth of an inch (Olson 1967). How does this tiny molecule displacement become meaningful to us?
Most of the human ear (see fig. 2) is located within the temporal bone of the skull. When sound waves arrive, they travel through the auditory canal until they reach the eardrum (tympanum), a piece of skin stretched over the end of the canal. At this point, the sound waves make the tympanum vibrate, in turn setting up vibrations in the ossicles of the middle ear. The ossicles move back and forth, and the innermost ossicle, called the stirrup or stapes, acts like a piston, pushing the boundary between the middle and inner ear in and out. This movement starts vibrations in the fluid of the inner ear, which are detected by hair cells in the cochlea. These cells send nerve impulses to the auditory area of the cortex, via the vestibulocochlear nerve (see fig. 3), where they are interpreted as sounds (McCracken 1999).
This
explains how sound travels to the brain; but is there anything unique about the
processing of music in the brain? Recent
research indicates that there is. In the
article entitled “Exploring the Musical Brain” (Scientific American,
For certain, it is becoming apparent that unexpected and
unsophisticated areas of the brain are sometimes involved
in interpreting, writing, feeling or performing music. As
some research has showed, even the visual cortex sometimes
gets into the act. Hervé Platel, Jean-Claude Baron and
their colleagues at the
emission tomography (PET) to monitor the effects of
changes in pitch. What they found – much to their
surprise – was that Brodmann’s areas 18 and 19 in the
visual cortex lit up. These areas are better known as the
“mind’s eye” because they are, in essence, our
imagination’s canvas. Any make-believe picture begins
there. Thus, Baron suggests that the brain may create a
symbolic image to help it decipher changes in pitch.
But music goes much deeper than that – below the
outer layers of the auditory and visual cortex to the
limbic system, which controls our emotions. The
emotions generated there produce a number of well-
known physiological responses…By monitoring such
physical reactions, Carol Krumhansl of Cornell
University demonstrated that music directly elicits a
range of emotions.
As
reported by Sarah Graham in the article “Scientists Refine Musical Map of the
Brain” (Scientific American, December 13, 2002), Scientists have also
identified the brain region responsible for registering tonality, the spatial
relationships between musical tones, located just behind the forehead. Petr Janata of
track the brain activity of eight volunteers as they listened to music. He states that “This region in the front of the brain where we mapped musical activity is important for a number of functions, like assimilating information that is important to one’s self, or mediating interactions between emotional and non-emotional information…The results help provide a stronger foundation for explaining the link between music, emotion and the brain” (Graham 2002).
Can scientific definition and study really understand music? Scientists can describe the physical manifestations of sound waves, ear functions, and brain activity, but does this really capture the nature of music? As part of this exploration, I decided to include an interview with a professional musician for the purpose of conducting an interdisciplinary approach.
Michael Pitre has played music for as long as he can remember, and has been a professional musician and music teacher for the last fifteen years. He is a composer and a singer, and plays trumpet, guitar, harmonica, and percussion. The following interview
takes an increasing metaphysical direction, as will be seen, as Michael tries to explain his understanding and experience of music.
Q. What is the nature of music?
A.: Music is all encompassing; it is the fabric of the world we live in.
Everything is music, and music is everything.
Q. What is the relationship between sound and music?
A. To me, everything is music. In general, people decide that some sounds
Are more desirable, and some are less. The more desirable sounds are
“musical.” But what is music to one may not be music to another; music
is in the ear of the beholder.
Q. Are you saying that any desirable sound is music? Aren’t there sounds
that are desirable to a person, such as the sound of a child’s voice to his
or her mother, that would not be defined as “music?”
A. The voice of a child is music to the mother’s ear, by my definition.
Q. What is your understanding of the scientific and mathematical relationships with music?
A. Some people call this a scientific or mathematical world; I call it a musical
world. There is a natural rhythm to the whole universe; the seasons are
the cadence of the earth.
Q. What about the mathematical relationship to tonal vibration?
A. I know in tune and out of tune; I never looked at the numbers.
Q. Has the ear of the beholder changed, as to what is considered to be music?
A. Harmonically, it’s pretty much the same, at least in the western world.
One, four, five [these are the chord numbers played in much of Western
Music – for instance, in the key of C: “one” would be a C-major chord,
“four” would be an F-major chord, and “five” would be a G-major chord].
The beats have changed. What people decide is palatable goes a long way
toward deciding what is deemed music or not [in a culture].
Q. What do you think?
A. I think music is too broad to attempt to dissect it in such a fashion.
Q. Would you agree with Helmholtz in his definitions of noise and music?
A. Once again, music is in the ear of the beholder; whatever is grouped, it
becomes, depending both on the broadmindedness of the listener and the
creator. The math of life is the math of life. Anytime you start trying to describe it in words, you are already lost; words do music an injustice. Music is not to be possessed, but enjoyed.
Q. You play a lot of jazz and blues, in which improvisation is prevalent.
In general, how important is improvisation in music?
A. How important is improvisation in life? Improvisation is adaptability,
which is of paramount importance in all realms. It requires trust in yourself and your abilities, and an understanding of music.
It is clear that there is little similarity in the approach of musicians and scientists to the study of music. As in a difficult marriage, perhaps the best way to get along is to allow each partner to do what he or she does best, without hindrance. The role, for instance, that science plays in music is that of a silent partner – one that allows for creation, and documents it unobtrusively. Science explains what happens in the physical world when music is made, and can describe how music is made, but science cannot make it. The musician, inversely, is able to create music without knowing how it works scientifically. Indeed, this lack of knowledge seems to be necessary to the creative process. In essence, the utilization of the visual cortex, the audio cortex, and the limbic system of the brain is perhaps best left unnoticed by the musician; too much consciousness and analysis appears to be detrimental to creativity.
Conversely, science will always have a limitation placed on its understanding of music, precisely because it cannot be defined strictly by sound waves, brain impulses, and biological functions. Perhaps that is best, as well, for the objective study that must be undertaken by the true scientist. With complete understanding comes subjectivity and judgment, which do not allow for detached observation.
For the scientist, music is physics; for the musician, music is metaphysics. For the rest of us, music is to be enjoyed and appreciated, and the scientific, yet miraculous, explanation of how it works adds a dimension of knowledge that can only benefit us.
Graham, Sarah.. “Scientists Refine Musical Map of the Brain.” Scientific American.
Helmholtz, Hermann. On the Sensations of Tone. Originally published by Longmans &
Company,
1877, translated by Alexander J. Ellis in 1885; republished by
Leutwyler, Kristin. “Exploring the Musical Brain.” Scientific American. January 22,
2001.
Retrieved from www.sciam.com
McCracken, Thomas, ed. New Atlas of Human Anatomy. MetroBooks, an imprint of
Friedman/Fairfax Publishers, 1999.
Olson, Harry. Music, Physics and
Engineering.