Jones. (1.1.1) Music Theory, [basic terminology of sound and music: introductory material]

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[The following is summary. Boldface and bracketed notes are my own.]

George Thaddeus Jones

Music Theory

Part I
Notation, Terminology, and Basic Theory

Chapter 1
Elementary Acoustics and the Properties of Sound

1.1 
[Introductory material]

Brief Summary:
Music is made out of sounds, which are air vibrations produced by vibrating material parts of musical instruments. If these vibrations are irregularly patterned and complex, they make noise. But if the vibrations are regular in their periodicities, they produce tones. A tone is characterized by four variable properties: {1} pitch (highness or lowness, depending on the wave frequency), {2} duration (the temporal extent of the tone), {3} Intensity (the volume or loudness of the tone, depending on the wave’s amplitude), and {4} timbre (the tone’s distinctive quality, depending on its overtone signature). Instruments can be classified by the primary material they are made of. But since our concern here is more acoustical, we distinguish them by whether they have vibrating strings, vibrating air columns, or vibrating bars, plates, or membranes.

Summary

We hear sound when vibrations traveling through the air strike and stimulate the eardrum. When these vibrations are irregular and complex, we normally classify them as noise. Regular vibrations, however, produce tones with a discernible pitch. (3) [Tone is not defined here, but from wikipedia: “A musical tone is a steady periodic sound”. For more on the periodicity of waves, see this entry on sine waves, and also see this entry on the physics of waves.]

The sound vibration “is produced by the oscillation of some elastic material, such as a stretched string” (3). These vibrations [of the solid material] are transmitted through the air by “forming areas of compression and rarefaction. One vibration in the air consists of one cycle or wave of high- and low-pressure  areas” (3). [See this entry for more on compression and rarefaction waves.]

“The number of these vibrations per second is called the frequency of the sound wave; the greater the frequency, the higher the pitch” (3). [A wave in water can be larger or smaller, that is, have a greater or lesser amplitude. In the air, the compression wave can also be more or less “massive” or pronounced.] “The strength or amplitude of the vibration controls the volume or intensity of the sound; the greater the amplitude the louder the sound” (3).

There are four main properties that characterize the tone:

1) Pitch: the relative sense of “high” or “low” [depending on the frequency of the sound wave’s oscillations]
2) Duration: the [temporal] length of the sound or rhythm
3) Intensity: the volume or degree of loudness [depending on the amplitude of the wave]
4) Timbre: the distinctive quality of the sound [depending on the “overtone” wave signature. Again see this entry on the physics of waves.]
(3)

There are other musical concepts that are of more interest for performance, for example “how the tone is attacked and released, how one tone is connected with another, and how a combination of tones produces a sense of density or texture” (3d).

“Musical instruments are mechanisms that produce, resonate, | amplify, and otherwise control vibrations” (3-4). Instruments can be classified in different ways. One way is to classify them according to the principal material they are made from, for example, brass and woodwind. “However, from an acoustical point of view, it is better to discuss the common musical instruments under the headings of vibrating strings, vibrating air columns, and vibrating bars, plates, or membranes” (4).

Jones, George Thaddeus. Music Theory. New York: Barnes & Noble Books / Harper & Row, 1974.