of Microprocessors

730 MUSICAL ApPLICATIONS OF MICROPROCESSORS
On the negative side, it presently costs substantially more to develop
and manufacture an all-digital synthesizer than a hybrid unit. If off-the-shelf
components are used in the design, engineering effort and tooling costs may
be affordable by a moderately small company, but then manufacturing costs
will be quite high. For example, the cost of a single parallel multiplier chip
can easily exceed the cost of 20 or more complete voltage-controlled
oscillators. On the other hand, using custom chips can bring manufacturing
costs down considerably, but then only the largest companies designing
instruments for the broadest possible mass market can afford the development
expense.
Nevertheless, at the time of this writing, "digital" is a hot buzzword
not only in the synthesizer market but also the audiophile ("compact disks")
and recording markets (digital multitrack recorders and all-digital studios).
If a product is "digital," it is seen to be inherently better even ifan objective
evaluation may show it to be less flexible or more difficult to use than an
equivalent oldet technology product. Thus, at this time, most new synthesizers
being introduced are mostly, if not all, digital.
Synthesis from Sound Parameters
The development of digital synthesizers seems to be going in three
rather distinct directions according to what designers perceive to be the
greatest strength of digital technology. One of these is simply synthesis jl-om
scratch according to sound parameters in a live-performance keyboard
instrument. The instrument's functional and design goals are similar to those
of a hybrid synthesizer but with the advantages of digital technology, such as
freedom from drift, present. Because of digital's inherent accuracy, digital
instrument designers expect to be able to concentrate on providing more
flexibility in parameter control and interaction and not have to worry very
much about tuning correction, error accumulation, and the like. Beyond a
certain sophistication point in the synthesizer's design, it becomes almost
free (in production cost terms) to provide additional synthesis algorithms,
more parameter modulations, and so forth. All that is really added is perhaps
more memory to hold the additional programming and data. In fact, the
flexibility limit in a live-performance keyboard instrument is often not set by
the circuitry's capabilities but by an inability to design an effective human
interface so that the user can learn the instrument in a finite time and
effectively use all of the features. This problem is far more serious than what
might be thought.
A good analogy might be word-processing programs for personal
computers. Obviously, any small computer and a letter-quality printer is
theoretically capable of producing any kind of text; it could even have typeset
this entire book less figures (and for $3,000 one can purchase a laser printer
that could typeset the text and draw all of the figures, except photographs, as
clearly as you see them here). The rules of written English are fixed, and most