The virtuoso demands that composers placed on musicians at the end of the 1800s were but a foretaste of things to come in the twentieth century. Members of the orchestra were complaining that the music of contemporary composers was unplayable because of the enormous difficulty of complex orchestral writing styles. With the Paris premiere of Igor Stravinsky's "Le Sacre Du Printemps" in 1913, it seemed that the limits of performability had been reached and that the music world was about to go over the brink.
After a break in compositional flow during World War I, composers explored new, uncharted musical domains. In the 1920s and 1930s, some composers created intricate and complex avant garde music, demonstrating the ultimate limitations of human musicians. They did not know it at the time, but these pioneers were attempting to write electronic music before the needed technology had been invented.
After World War II, European composers began to experiment with a new invention, the tape recorder. Here was a medium in which an artist could actually hold sounds in her own hands. Chopping up a tape recording and reassembling the pieces in a different order opened up a new world of sounds for composers to explore. It also required artists to come to grips with the phenomenon of sound itself, and questions like what it was made of and how sounds differed from each other. These problems were eventually solved on paper but a real tool was required to give composers the ability to actually manipulate the building blocks of sound. In the 1950s, electronics technology had been developed to the point where it was finally able to meet this demand, leading ultimately to the development of the first music synthesizer by Harry Olson and Herbert Belar in the laboratories and studios of RCA.
The synthesizer is a device that creates sounds electronically and allows the user to change and manipulate the sounds. All sounds in nature consist of waves of varying air pressure. A synthesizer creates sounds by generating an electrical signal in the form of a waveform, usually either a sine wave or other simple mathematical wave, which is amplified and used to drive an acoustic speaker. Unfortunately, the sound quality of a simple waveform is somewhat raw and unmusical, at least to most people. The waveform is usually altered in numerous ways, using filters to create the interesting timbres, or colors, of sound that are usually associated with certain acoustical instruments. Changing the frequency of the waveform raises or lowers the pitch of the sound. A synthesizer can control and change the beginning attack of a sound, its duration, and its decay, in addition to controlling the waveform itself.
Synthesizers can receive information from numerous sources about how to set the different parameters of its output sound. Any electronic device, such as a computer program, or person can control the synthesizer. An obvious way to accomplish this is to build the synthesizer in such a manner that it resembles an already-existing musical instrument, such as a piano. A piano-like keyboard is often used to generate signals that control the pitch of the synthesizer, although a keyboard is not required, or even necessarily desirable, to do the job. One of the first commercially available keyboard-based synthesizers marketed to the general public was built by Robert Moog in the 1960s. Other early competitors of the Moog Synthesizer were built by Don Buchla and Al Perlemon.
All of the early synthesizers were built using analog computer technology. Since the late 1970s, however, digital synthesis has developed as the premiere technology in synthesizer design. In the process of digitally recording a sound, called sampling, any sound recording can be converted into a series of numbers that a computer can analyze. The computer takes snapshots of the sampled sound in very short increments, about forty thousand times a second. Mathematical techniques, such as Fourier analysis, are then used to calculate the complex waveform of the original sound. The sound can then be easily reproduced in real-time from a synthesizer keyboard. This technique for creating sounds, and others, form the design basis of most digital synthesizers such as the New England Digital Synclavier and the Kurzweil music synthesizer. The same technique can be applied to synthesize drums, voices or any other kind of sound. Digital instruments can also receive input not just from a keyboard, but from the actual breath of the performer, for instance. Digital flutes and other wind-instrument synthesizers convert the force of the musicians breath into a signal that can modify any desired parameter of the output sound.
Synthesizers have shown themselves capable of creating a wide variety of new and interesting sounds. Their one limitation, of course, is that they sound only as good as the speaker that amplifies their signal. Most humans can hear sounds far beyond the range that even the best speakers can reproduce, sounds that acoustical instruments have always been capable of generating. Because of this limitation, and others, synthesizers are not viewed as replacements of traditional instruments, but rather as a creative tool that enhances the musician's already rich palette of musical possibilities.