Based on cluster voltage control, this instrument could be regarded as the predecessor of the Electone GX-1. Although it looked just like an Electone, the GX-707 was actually an eight-note polyphonic synthesizer—more specifically, the upper and lower keyboards supported eight-note polyphony, while the solo and pedal keyboards were both monophonic. As the flagship model in the Electone lineup, however, this prototype was conceived of as a “theatre model” for use on the concert stage. With a console weighing in excess of 300 kg and a separate board required for editing tones, it was not well suited for sale to the general public, and to this day is still considered a niche instrument. Yet the GX-707 did possess extremely expressive tone generators, technology which Yamaha elected to use in a separate solo-part keyboard product for use with existing Electones. Thus was born the SY-1 monophonic synthesizer, which became Yamaha’s first synth upon its release in 1974. Given that analog synthesizers have typically evolved from monophonic to polyphonic, this reverse pattern—namely, moving from poly to mono—is further evidence of Yamaha’s unique way of thinking.
Although the SY-1 lacked a key assigner, it did feature an envelope generator for altering its sounds over time. The envelope generators used in synthesizers typically comprise four stages, identified by the letters ADSR. “A” stands for attack time—that is, the adjustable time between pressing of a key and the resultant note reaching its peak level. The decay time—represented by “D”—defines how long it will take when the key is being held down for the sound to drop from this peak to the sustain level. This sustain level, indicated by “S”, is the constant volume that held notes ultimately reach. Last but not least, the release time—represented by the “R” in ADSR—specifies how long it will take for the sound to fade away completely once the key has been released.
Normally, one would use a controller for each of these parameters to adjust how the sound should change over time in response to playing, holding, and releasing the keys. However, we can clearly see that the SY-1 control panel lacks the knobs provided on modular synths such as the Moog and Minimoog for configuring the ADSR stages of amplitude and filter envelopes. Instead, a pair of sliders labeled Attack and Sustain are used to adjust the amplitude envelope, and a feature known as Attack Bend allows the pitch and filter envelopes at the beginning of the note to be adjusted in a unique way.
The SY-1 featured a range of preset envelopes for recreating the sound of various instruments such as the flute, guitar, and piano, which could be activated simply by moving the tone levers. Today, we take it for granted that synthesizer presets can be easily recalled, but Yamaha’s inclusion of this functionality in its very first analog synthesizer was highly innovative.
Another groundbreaking feature of the SY-1 was touch control, or what is commonly known today as velocity sensitivity. Prior to the introduction of the SY-1, electronic organs had typically been equipped with a volume or expression pedal that the musician could use to modulate the sound for greater expression while playing. Yamaha had, however, been working on a range of different prototypes with the aim of modulating tone based instead on how hard the keys were played. Ultimately, we perfected a technology that measured the strength of playing by detecting how long it took for keys to be fully pressed down, and it was this system that we debuted in the SY-1.