242 lines
14 KiB
Plaintext
242 lines
14 KiB
Plaintext
Computers and Music
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By Robert A. Moog
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[Robert A. Moog is the inventor of the practical music synthesizer and
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president of Big Briar, Inc., a Leicester, North Carolina, firm specializing
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in the design of custom electronic instruments.]
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For some of us, the idea of an electronic muse is scary; after all, music is
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an essentially human activity, while electronic equipment, especially the
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computer, is "mechanical" and "unnatural." Throughout history, however, music
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has been closely linked to technology. Except for the human voice, the
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instruments of music-making have always been "high-tech" in their time.
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THE ELECTRONIC MUSE
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-------------------
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The violin, pipe organ, and trumpet are complex constructions that were as
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"unnatural" when they were first developed as the computer is today. The
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piano and saxophone, those vital elements of our musical experience, were
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triumphs of manufacturing technology a century ago. Musical instrument
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designers have always employed the most advanced technology of their time.
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Now, in our time, electronic and computer technologies are preferred for new
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musical instrument development.
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But this is not to say that musicians are embracing electronics just because
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it's the "latest thing." As a group, musicians favor instruments that
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a) sound good and b) offer musically useful ways of manipulating sound.
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Increasingly, musicians are drawn to electronic instruments -- not because
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they're easy to play or sound like traditional acoustic instruments, but
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because they offer new tone colors and new ways of making music.
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What's more, musicians have been experimenting with electronic instruments
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ever since the first vacuum tube was invented three-quarters of a century ago.
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Even before that, musicians and musical instrument builders were collaborating
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to harness the forerunners of electronics and computers to the service of the
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muse.
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For a growing number of musicians, computer technology is the greatest
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advance since the invention of catgut. Music is a form of communication -- of
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organizing and transmitting data. The "alphabet" of music consists of notes.
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Melodies, chords, and rhythmic patterns are the "words" and "phrases" of
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music. Just as computers can generate "characters" to make text or a graphic
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design, they can also process a stream of numbers that represent a sound
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waveform. And just as word processing programs endear computers to
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wordsmiths, today's composers, performers and music teachers are all exploring
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the computer's ability to handle musical information.
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If you understand the general principles of computer operation and if you like
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to listen to music, you'll have no trouble following the many ways that
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digital technology and computers can be used to make music. Just keep in
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mind that computer music is a natural extension of traditional music and uses
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programs that are only slightly different from your basic word processor or
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data handler. As we shall see, simulating a multitrack recording studio on
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your monitor screen is done with software that is directly related to the
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program used to "compose" this article.
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MUSICAL DIGITS
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--------------
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All sounds, musical or otherwise, are vibrations of the air, at rates of
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roughly 20 to 20,000 times a second. If the vibrations repeat regularly, the
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sounds are pitched (like a guitar or clarinet tone). If a sound vibration
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does not repeat regularly, then it sounds pitchless or "noisy" (like a cymbal
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crash). In a pitched sound, the rate of repetition is called its frequency;
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the greater the frequency, the higher the musical pitch of the tone. The
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strength of the vibration is called its amplitude; the greater a sound's
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amplitude, the louder it is.
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The shape of a vibration is called the waveform. You can think of the
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waveform of a sound as the graph of the air pressure at a particular point
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over time. The waveform is an abstraction that we use to describe the sound.
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It happens to be n abstraction that has a lot to do with the tone's perceived
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quality.
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A loudspeaker (speaker, for short) is a device that converts electronic
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vibrations into sound. In talking about electronic music and computers, we
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generally refer to electrical waveforms that exist inside an instrument's
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circuitry. When we refer to these waveforms as if they were sounds, we assume
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there's a speaker somewhere and that we're using it to produce the sounds.
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A personal computer may contain its own small speaker (e.g. the Apple ][), may
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use the speaker of the TV to which it is connected (e.g. the Atari or
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Commodore 64) or may require connection to an external sound system like most
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high-quality music synthesizers. Most electronic pianos, organs, and
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synthesizers use "analog" circuits that produce smooth waveforms. Digital
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computer circuits, on the other hand, work by switching on and off.
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How does a computer produce a musical tone? In most computers, you can turn
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the speaker on and off as is it were, say, a memory location. You can produce
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a tone by writing a simple program to a) turn the speaker current on, b) wait
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a very short time, c) turn the speaker off, d) wait again, and e) repeat the
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above steps a specified number of times. The waiting time determines the
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pitch of the tone, while the number of cycles determines its duration.
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If the "speaker off" and "speaker on" times are the same, the resultant
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waveform is called a square wave and the musical quality is somewhat hollow,
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like that of a clarinet. If the "speaker on" and "speaker off" times are not
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the same, the waveform is called "rectangular" and the quality may be
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saxophone- or oboe-like. If the "speaker on" and "speaker off" times are
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programmed to change randomly, the resultant sound is a pitchless noise.
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While any other computer can produce square and rectangular waves, only those
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equipped with sound and synthesizer circuits can produce more complex
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waveforms. Some sound synthesizers are built on single integrated circuit
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chips that can be programmed to produce a wide variety of waveforms and
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envelopes. (The envelope of a sound is its outline as it builds up, sustains
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and dies out.)
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Other synthesizers are built on circuit cards that plug into the computer or
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may be completely separate or peripherals. Computer programs enable musicians
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to design their own sounds. Musicians think of this type of programming as
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"building an instrument": the "instruments" exist as data that define
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waveforms and envelopes--and may therefore be stored in "libraries" on disk or
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tape.
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Computer-controlled sound synthesizers may be all-digital (the waveform itself
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is generated from digital data), all-analog (waveforms are produced
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continuously by analog circuitry that responds to digital instructions) or a
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combination of the two (waveforms are converted from digital to analog form,
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then passed through analog circuitry). Digital circuits that produce waveforms
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are made up of steps that are often audible. Both methods of synthesis have
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their advantages and limitations; some musicians prefer the smooth,
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distortion-free analog waveforms, while others favor the accuracy and
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versatility of digital generators.
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PLAYING THE PC
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--------------
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There are simple programs for most personal computers to make scales and
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melodies through the computer's speaker. To use a typical program of this
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kind, you type in codes for the pitches and durations of the notes.
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More sophisticated programs enable you to vary the rectangular wave tone
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color, adjust the overall tempo, produce trills and glides, and store tunes
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that you have programmed on disk or cassette tape. Music Maker, a software
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package for the Apple ][, produces the illusion of two notes being played
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simultaneously, generates sound effects as well as musical tones, and displays
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a colorful animated video pattern in time with the music. Programs like Music
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Maker don't produce complex or high-quality tones; their main uses are
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educational and recreational -- you can learn a good deal about programming,
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train your ear and have a lot of fun, for a very small investment in addition
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to your computer.
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By using a computer with a built-in sound synthesizer, or adding a digitally
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controlled synthesizer peripheral, you can make music with a wide variety of
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interesting tone colors. The Commodore 64 has one of the most versatile
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built-in synthesizers of any currently available personal computer. The "64"
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uses a proprietary chip that produces three tones with programmable waveform
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and envelope. The chip also contains an analog filter, a device that changes
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the tone color by emphasizing some of the sound's overtones and cutting out
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others. The resulting range and quality of sound rival that of some of the
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analog keyboard synthesizers available in musical instrument stores.
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Some of the most musically advanced computer programs are designed around the
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Mountain Computer Musicsystem, an eight-voice digital tone generator for the
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Apple ][. Among the more popular are the Alpha Syntauri and the Soundchaser
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systems. Both use the Musicsystem in combination with a professional-style
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four- or five-octave music keyboard and their own operating software.
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With either of these systems you can make up your own sounds, play them from
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the music keyboard and record the keyboard performance. Since one part of the
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software sets the Musicsystem up to produce the desired tone colors and
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another part captures and stores the keyboard performance, you can play back
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your keyboard performance with a variety of tone colors, pitch ranges, and
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speeds. Both the Alpha Syntauri and the Soundchaser can implement the basic
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functions of a multitrack recording studio. You can record a keyboard
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performance on one "track," then play that track back while recording
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subsequent tracks. The Syntauri Metatrak program, for instance, lets you
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record up to sixteen tracks, then play them back simultaneously. Fast
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Forward, Rewind, Record, and Erase functions are implemented by typing one or
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two characters on the computer keyboard.
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To a musician, using Metatrak (or the Soundchaser Turbotracks program) is
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closely akin to using a conventional tape recorder. To the average computer
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user, programs that implement a multitrack recorder are actually file
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management systems with real-time merging capability. Whichever way you look
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at it, Metatrak, Turbotracks, and related programs offer potent musical
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resources to pro musicians -- and a lot of musical enjoyment to amateurs.
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In addition to simulating multitrack recorders, computer-based music systems
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offer other functions that are important to musicians. Music-teaching
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programs are available for both the Soundchaser and the Alpha Syntauri.
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Soundchaser's Musictutor package contains an array of ear-training exercises
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that not only sharpen your ears, but keep track of your musical progress.
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Syntauri's Simply Music program will teach you how to play a keyboard
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instrument in a variety of styles and at a pace that suits you. Once your
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keyboard chops are in good shape, you can convert your keyboard performances
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directly to a printed score with Syntauri's Composer's assistant, a software
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package that enables a dot-matrix printer to produce conventional music
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notation.
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COMPUTER CONTROL
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----------------
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The Roland Compumusic CMU-800R is an example of an analog musical sound
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generator designed for computer control. The Compumusic uses electronic
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piano, organ, and synthesizer circuits to produce realistic percussion, bass,
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"rhythm" guitar and melody voices through your sound system. Using ROland-
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supplied software, you program the melody, harmony, and rhythm from the
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computer keyboard. Then you "mix" the sounds by manipulating the volume
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sliders on the Compumusic unit while the computer "plays" the complete piece
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of music that you've programmed. The computer is not able to program the
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Compumusic waveforms since these are determined by the unit's analog
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circuitry. The advantages of Compumusic are in its high sound quality and
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hands-on-the-knobs control.
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Musicians have expressed the desire to control a regular electronic keyboard
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by means of a computer. An increasing number of electronic pianos, organs,
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and synthesizers are being adapted for computer control. For this purpose,
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the musical instrument industry has developed an interface called MIDI, the
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Musical Instrument Digital Interface. MIDI allows electronic instruments,
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computers, and similar devices to be connected with a minimum of fuss. This
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means that, if your computer itself is equipped with a MIDI peripheral and the
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necessary software, you can use your computer to control any MIDI-equipped
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musical instrument. You can even combine instruments into a computer-
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controlled "orchestra."
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Will computers ever completely replace human musicians? A number of
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traditional instrumentalists, upon seeing entire string and horn sections
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replaced by synthesizers and other digital instruments, have asked this
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question. The answer lies in the fact that music is and always will be an
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aesthetic and emotional experience for humans and not for computers. There
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will always be musicians as long as there is a song in our hearts.
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X-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-X
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Another file downloaded from: The NIRVANAnet(tm) Seven
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& the Temple of the Screaming Electron Taipan Enigma 510/935-5845
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Burn This Flag Zardoz 408/363-9766
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realitycheck Poindexter Fortran 510/527-1662
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Lies Unlimited Mick Freen 801/278-2699
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The New Dork Sublime Biffnix 415/864-DORK
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The Shrine Rif Raf 206/794-6674
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Planet Mirth Simon Jester 510/786-6560
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"Raw Data for Raw Nerves"
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X-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-X
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