The structural independence of the performance device in an electronic musical instrument has three major potential benefits. First, the design of an electronic performance device can be ergonomic and comfortable to play. A violin, for example, is not ergonomic and has the potential for inflicting serious physical harm on its user: the wrist and hand positions that must be used to play the notes and hold the bow are unnatural and often lead to tendonitis. Second, the performance device in an electronic musical instrument can be chosen by a composer to perform a musical task suitable to the performer’s role. Waving one’s hands in the air, for example, might suggest conducting, while playing a keyboard with one’s fingers suggests playing a traditional instrument. Third, because the performance device generates controls for the operational variables of the sound generator, it can be optimized for every musical situation.

The structural independence of the sound generator has two major benefits. First, the sound generator can produce a richer aural experience for a performer. Whereas the sound generator of an acoustic instrument produces one characteristic sound (a violin, for example, produces a violin sound), an electronic sound generator typically produces many different sounds. Second, because the sound generator contains the variables for which controls are generated by the performance device, a particular sound generator can be chosen according to its suitability to a particular musical task.

The most important differences between an acoustic instrument and an electronic instrument, however, are in the link that connects the performance device to the sound generator. First, the link is itself configurable. Unlike the bridge in a violin which transmits a performer’s complex and interdependent group of sound parameters (such as pitch, loudness, vibrato, and articulation) to a single sound generator, the link in an electronic musical instrument can connect any aspect of a performance gesture to any number of sound variables in any way, allowing for great performance flexibility. Performing an electronic musical instrument is not unlike flying a fly-by-wire airplane where the pilot’s instructions are interpreted and linked by a computer to generate controls for the many variables of the airplane’s control surfaces.

Yet more important, whereas the link in an acoustic instrument is essentially passive, offering no more information than that which is specified by the performer, the link in an electronic musical instrument can be active. The link, in other words, can itself generate musical information that complements or shares control of the musical process with the performer. Unlike a traditional instrument in which a performer’s control is passed directly to the sound generator, in these information-generating instruments the performer performs the control system, which adds its own information to what the performer specifies. In this situation, the performer and the automatically-generated controls share control of the instrument; and if the automatically-generated information contains some unpredictable elements, the performer becomes an improviser, reacting to the information generated by the instrument he/she is playing.

What are the implications for this in the functioning of the separate components of an electronic musical instrument?