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Appendix B Synthesizer Basics 500
Storage and polyphony
Customers weren’t entirely satised with the Minimoog and contemporary synthesizers, however.
Although musicians no longer had to contend with countless cords in order to play a synthesizer,
they still had to deal with numerous knobs and switches before they could do something as
simple as switch from one sound to another. Moreover, keyboardists were bored with playing
monophonic melody lines on synthesizers—they wanted to play chords. Although dual-voice
keyboards that connected two monophonic synthesizers were available as early as 1970,
customers wanted more.
Attempting to satisfy these demands, two schools of thought emerged in synthesizer design.
One approach called for an independent, monophonic synthesizer to be assigned to every key
on the keyboard. To this end, designers married the design principles of electronic organs to
synthesizer technology. Although this breed of instrument was fully polyphonic—all notes of
the keyboard could be heard simultaneously—it wasn’t as versatile in its control options as a
true synthesizer. The rst fully polyphonic synthesizer to feature this type of design was the
Moog Polymoog, released in 1975. Developed primarily by David Luce, it featured 71 weighted,
velocity-sensitive keys.
In the second approach to polyphonic sound generation, a synthesizer was assigned to a key
only when the key was pressed—in eect, semi-polyphony. As early as 1973, American company
E-MU Systems introduced the Modular Keyboard System Series 4050, a digital keyboard that
could be connected to up to ten monophonic synthesizers, and thus had ten-voice polyphony.
The problem with this approach was that very few people owned ten synthesizers, and the
amount of time and eort involved in programming a new sound was an overwhelming
deterrent. Digital memory was still waiting to be developed, and, once again, the evolution of
semi-polyphonic synthesizers required the qualities that only digital keyboards could provide.
The same prerequisite—digital engineering—eventually led to synthesizers that allowed sounds
to be stored. Without the benet of digital technology, early attempts at storing sounds included
some unusual solutions. For example, a synthesizer with analog programmability required a
dedicated row featuring all of the instrument’s control elements for every “memory” slot. In this
case, a selector switch accessed one of the many identical control panels and connected it to the
sound generator.
The rst synthesizer featuring storage slots implemented in this manner was the 1975 Yamaha
GX1. The control elements for the system’s storage slots were so small that they could be
adjusted only by using jeweler’s screwdrivers and complicated tools—called programmers
and comparators.
It was not until 1978 that the problem was resolved. The ve-voice polyphonic Prophet-5,
released by the American company Sequential Circuits, was the world’s rst synthesizer with
a global storage feature. All settings for each of its ve onboard monophonic synthesizers
were stored in memory slots—40 in the debut model. Moreover, all ve synthesizers shared a
single user interface, which simplied matters considerably. In spite of its initially high price,
this instrument proved extremely popular and approximately 8,000 were built up until 1985. In
addition to its digitally implemented polyphony and memory, the success of the Prophet-5 is
due to the quality of its analog sound generation system.