DEFINITIONS MUSIC IS SOUND ORGANIZED IN TIME
The broadest definition of music is “sound organized in time.” Many kinds of sounds—including noises and tones produced by any means, not only by musical instruments— can be used to create music, particularly in the modern era. All that is required is a time frame, sound waves, and a cognizant mind to perceive and interpret those sounds. Common but not required factors include a person (often called a composer) who first imagines the music, human or mechanical performers to generate the sounds, and a mechanical means of recording and reproducing them. Sometimes the composition and performance happen simultaneously (often as improvisation, but sometimes via electronic composition). Some degree of human intention and perception are necessary for music to exist but defining this exactly continues to puzzle scientists and philosophers, who debate questions like whether a birdsong can qualify as music, whether accidental sound can be music, or whether a phonograph playing in the forest is music if no one hears it.
MUSIC OF THE WESTERN WORLD
It should be noted that many cultures have different views of music; in some cultures, music is so interconnected with ritual, language, dance, and other aspects of life that in some languages there is no separate word for “music.” At certain times in history, Western traditions have encountered and incorporated the music of non-Western cultures.In recent decades, globalization has made the boundaries between Western and non-Western culture increasingly permeable. Nonetheless, the material in this guide will pertain to what is called the “music of the Western World”- --the musical traditions that developed in Europe in the past two millennia and their cultural extensions in the Americas.
THE PHYSICS OF MUSICAL SOUND SOUND WAVES
In the abstract, sound is described as a wave of energy. As a wave, it has both amplitude and frequency. The amplitude affects the decibel level, or how loud or soft the tone is. The higher the amplitude of a sound wave, the louder it is. The frequency affects the pitch, which is the highness or lowness of the sound. The greater the frequency of a sound wave, the higher its pitch. When the frequency of a wave is between 20 and 20,000 cycles per second, the normal human ear hears it as a single, sustained tone. A pure sine wave at 440 Hz (cycles per second) sounds like an A above middle C. Orchestral musicians in the United States usually tune their instruments to “A-440,” meaning 440 Hz. Of course, not every sound has a regular frequency. When you drop a book on the floor, the sound quickly dies down and has no discernable pitch because the wave pattern is so irregular and short. Thus, there are two kinds of musical sounds: pitched and non-pitched. Percussion instruments provide most of the non-pitched sounds in music.
INSTRUMENTS AS SOUND SOURCES
How is a musical sound wave produced? In the late nineteenth century, two ethnomusicologists (the modern term for scholars who study the music of other cultures, or who study multiple cultures comparatively), Curt Sachs and Erich von Hornbostel, categorized instruments into four groups. Chordophones, such as violins, harps, and guitars, have one or more strings that are plucked, bowed, or struck; the vibrating string creates the sound wave. Aerophones (brass and wind instruments such as the many varieties of horns and flutes) feature a vibrating column of air. Membranophones have a skin or other membrane stretched across some kind of frame. The membrane, but not the frame, vibrates when struck. With idiophones, the body of the instrument itself vibrates when struck. Some examples of idiophones are bells, woodblocks, and xylophones. A fifth category was added later: electrophones, which create sound waves using a mechanical device known as an oscillator and are dependent upon electricity.
Centuries before Sachs and Hornbostel, Western orchestral instruments were grouped into “families.” These categories are still used for Western instruments today. Strings or stringed instruments are usually bowed or plucked. Brass instruments, which are aerophones made of metal, are sounded by the performer’s buzzing lips, which make the column of air vibrate. Woodwind instruments are also aerophones in which the column of air is moved by breath alone- --as in the case of flutes, recorders, and related instruments---or by one or two vibrating reeds usually made from wood. Percussion instruments include membranophones as well as idiophones, plus some chordophones that are struck rather than bowed or plucked, such as the piano. In some cases, keyboard instruments constitute a fifth category. TABLE 1-1 lists the most common members of each family of instruments.
Centuries before Sachs and Hornbostel, Western orchestral instruments were grouped into “families.” These categories are still used for Western instruments today. Strings or stringed instruments are usually bowed or plucked. Brass instruments, which are aerophones made of metal, are sounded by the performer’s buzzing lips, which make the column of air vibrate. Woodwind instruments are also aerophones in which the column of air is moved by breath alone- --as in the case of flutes, recorders, and related instruments---or by one or two vibrating reeds usually made from wood. Percussion instruments include membranophones as well as idiophones, plus some chordophones that are struck rather than bowed or plucked, such as the piano. In some cases, keyboard instruments constitute a fifth category. TABLE 1-1 lists the most common members of each family of instruments.
The first electronic instruments began to appear in the first decades of the twentieth century. The theremin is one of the best-known early electronic instruments and is still occasionally used today. When playing this instrument, a performer regulates frequency with one hand and amplitude with the other by disturbing the electrical fields that surround the protruding bars.
The next crucial step in electronic instruments came at the end of World War II. Enormous advances in electronics and radio technology had been made for wartime purposes, but after the war, many state-of-the-art studios were no longer needed for military purposes. Within a few years, scientists and composers began collaborating to make art with the new equipment. Electronically generated sounds and sounds produced by live instruments were recorded on tape, where they could be edited, manipulated, and mechanically recombined to form collages of sound that were “performed” via loud speaker. This type of composition was first known as musique concrète; the term used is French since the first practitioners were based in Paris. The basic techniques of tape music (later followed by more purely electronic music produced on computers) are looping and splicing, both of which permit compositions that cannot be reproduced by a human performer. Rome, Paris, Cologne, and New York City all had famous postwar centers for electronic music.
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