of Microprocessors

SOME REAL ApPLICATIONS 735
customer has shown only moderate interest. To broaden its appeal to
performing keyboard players, new features allowing greater flexibility in
modulating the stored sounds and routines for computing and temporarily
storing synthetic as well as sampled live sounds have been added as well as a
MIDI interface.
"Toolbox" Synthesizers
The third developmental direction (and solution to the man-machine
interface problem) is what will be called a "toolbox synthesizer." These
provide a large collection of more or less disjointed software and hardware
tools that can be used in sequence to build a composition. The control
interface problem is greatly simplified because each tool performs a specific
function and can be designed and implemented independently. It is the user's
responsibility to determine how to use the functions together to produce a
desired result. While they can be useful in live performance, a toolbox
synthesizer is really a studio synthesizer. As such, the major design goal is
maximum flexibility rather than efficiency in a performance environment.
Let's briefly look at what some of these tools might be and the sequence
in which they might be used to produce, say, a low-budget film soundtrack.
The composer would typically have a preliminary edit of the film and
instructions from the director available. With these, a detailed list of the
kind of music needed for each scene and its required duration is prepared.
Next, musical ideas and score fragments are composed and notated using
whatever method is familiar to the composer. Using the available score entry
programs on the synthesizer, the score is then entered. Typical methods
include direct music keyboard playing and the use of one or more music
languages. After entry, score segments can typically be saved and inserted
elsewhere, repeated, and modified in various ways such as transposition. For
film work, it is also necessary to adjust the segment durations to match the
scenes. This may be accomplished by deleting or adding phrases and small
adjustments in tempo.
Once the score, which may be just the melody line, is in the system,
the next step is orchestration. Up to now, some stock voice was probably used
and the score was devoid of dynamic and voicing markings. One approach
would be to search a library of already "designed" voices but, of course, it is
more creative to construct new ones. Usually there are many different "voice
editor" programs available using different synthesis techniques. For example,
one program may allow the drawing of individual harmonic envelopes for use
by an additive synthesis process. Another may allow interactive control over
an FM synthesis setup or interactive drawing of nonlinear distortion curves or
interactive design of digital filters. Yet another would begin by digitizing a
natural sound and provide numerous ways of modifying or distorting it.
Once a library of voices is constructed, the score is edited again to
include voice selection, dynamics, and additional musical lines. Depending