Chapter 1: Origins of the Yamaha Synthesizer
Evolution from the Electone
Technologies and products that could be seen as prototypes for the first electronic musical instruments have been around since the 1920s, but none has developed in closer association with popular music than the electronic organ. The Electone® ("Electone" is the product name (and trademark) used for Yamaha's electronic organs) debuted in 1959 with the D-1. Similar musical instruments based on vacuum-tube technology were already available at the time, but the D-1 was revolutionary in that its modules relied on transistors alone. Although the Electone set the stage for the modern synth in terms of sound synthesis, it lacked the expressivity of acoustic instruments to such a degree that the president of Yamaha at the time referred to it as a mere "musical toy." The instant one played a key, the instrument produced a tone that ceased immediately with an abrupt mechanical cutoff sound when the key was released.
Various research projects at that time had identified the way in which a tone changes over time as the most important factor in our interpreting it as the sound of a musical instrument. Let's consider the piano as an example: the tone produced when a key is played includes complex harmonics generated by the physical striking of the string. As the sound sustains, however, it gradually comes to resemble a wave with less harmonic content—such as a sine wave. This specific sonic variation over time is the most distinctive characteristic that allows us to identify the sound of the piano. Yamaha realized that the development of technologies capable of recreating these changes in a sound would be critical if electronic instruments were ever to produce the natural-sounding voices of acoustic instruments. In reality, Yamaha's history of synthesizer development actually began with this variation of sound over time and our quest to make the Electone produce more interesting sounds.
Why Digital Technology in an Analog Synth?
The tone producing system used in the first-generation Electone was extremely simple. Each key on the keyboard had its own oscillator—or what we now call a “tone generator”—which would generate a sound whenever its key was played. If the keyboard had 40 keys, the instrument would have 40 oscillators, with each pair operating in much the same way as a switch and buzzer. In reality, an octave divider—a device that can divide frequencies by any integer value—is used to produce tones in lower octaves; therefore, an instrument just needs enough oscillators to produce the 12 highest notes in its range—namely, top octave division method. Nevertheless, the decision to use new circuits capable of modifying sound over time as described above would thus have meant providing one for each and every key on the keyboard. Given the state of technology at the time, however, this would have made the design extremely expensive and resulted in an instrument that was unfeasibly large.
It was thus clear that new control technology would be required in order to use a limited number of circuits in a more effective manner. If, for example, an instrument had eight control circuits, it could generate up to eight polyphonic tones—that is, eight different notes at the same time. But if it also had 36 keys in a three octave configuration, this new technology would need to know which of the circuits to trigger in response to the playing of a particular key. Our solution was to introduce a device that could assign circuits to keys efficiently, based on the order in which they were played, the total number of keys currently being held down, and other related factors.
This type of device was known as a key assigner, and it can rightly be called the predecessor of today's dynamic voice allocation (DVA) technology. Back in the early seventies, when tone generators still relied on analog technology, digital circuitry was already being put to use in these key assigners. As such, their adoption was an important milestone in the introduction of digital technology in the analog-synth era.
Birth of the SY-1
In 1973, Yamaha completed development work on a prototype codenamed the GX-707. 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.
Crossover to CS Series Combo Synthesizers
In 1975, one year after releasing the SY-1, Yamaha introduced the GX-1 as a concert-model Electone; however, the first non-Electone products to inherit the unique technologies of the SY-1 were the combo synthesizers of the CS Series.
One of the most notable features of the CS synths was the integrated circuitry used in their tone generators and controllers—components that had up until then taken the form of transistor assemblies. This integration of state-of-the-art technology paved the way for huge weight reductions and vastly improved portability. Consider, for example, the GX-1 and the CS-80—the top-of-the-line CS synth: while these two instruments certainly differed in terms of design and mode of use, the GX-1 weighed in at over 300 kg and had a price tag of seven million yen, but the CS-80 was only 82 kg and cost just 1.28 million yen, meaning that the individual musician could both afford it and move it around.
Yamaha synthesizers at the time had two very distinctive features, the first of which was the ability to retain programmed sounds. These days, we think nothing of storing our original sounds in an instrument's memory in much the same way as saving a file on a PC. Back in the seventies, however, neither RAM nor ROM yet existed, so an extremely analog approach was employed to store sounds. The following illustration shows part of a page from the CS-60 service manual, which was used by technicians when repairing the instrument. This section, titled (Tone Preset 1) Circuit, contains instrument names, resistance values, and a circuit diagram. The synthesizer's levers were connected to variable resistors—that is, circuit elements that can limit current and voltage. As shown, however, fixed resistance values corresponding to specific positions of these levers are built into this circuit. The combination of these values resulted in a certain sound or tone, leading these circuits—which were widely used back then—to be called "tone boards."
In instruments like the GX-1, tone boards were physically inserted and removed to change sounds. As such, Yamaha was already at that time employing a sound storage method not unlike analog-type ROM cartridges. The CS-80, meanwhile, possessed functionality that allowed instantaneous switching between four original sounds. Specifically, it had four complete sets of memory elements, with one memory element from each set corresponding to a specific instrument controller. Each of the four sets could thus be used to store all of the controller positions for a user-created sound.
The other distinctive feature of Yamaha synthesizers was IL-AL type envelope generators. IL and AL refer to Initial Level and Attack Level, respectively, and these envelope generators used a slightly different approach to that of the standard ADSR type. In an ADSR envelope, the value corresponding to the very start of the attack stage is the base value, zero. When we apply the envelope produced by such a generator to a filter, the tone at the start of the sound is determined by the current cutoff-frequency setting; however, the tones at the peak of the attack and while the note is being held are defined by this cutoff-frequency setting in combination with the envelope generator depth and the sustain-level value. Because these tones are thus the result of multiple settings, adjusting the way in which a sound changed over time could become quite confusing. In contrast, when applying an envelope with Initial Level and Attack Level settings, the filter's cutoff frequency determines the tone produced while the note is being held, and the IL and AL controllers can set the tones at the start and peak of the attack stage independently. This approach provides a much higher degree of freedom, especially when trying to recreate natural-sounding tones. As a unique Yamaha feature, the IL-AL type envelope generator further demonstrates the commitment of our developers to high-quality sound creation.
The CS-80 was also equipped with a portamento bar known as the ribbon controller, which could be used to bend the pitch smoothly, and aftertouch functionality that could detect the pressure applied to each key being held down and change the tone accordingly. Given that these functions remain extremely popular in modern synths, the fact that Yamaha devised and implemented them four decades ago underscores the technical excellence of our synthesizer development team.
Lower Prices, More Compact Designs, and Further Enhancement
In the latter half of the seventies, we expanded the CS Series with low-priced, monophonic synthesizers, and as amateur musicians could now afford these instruments, they grew in popularity. Thanks in part to rapid advancements in electronic circuit integration and the resultant lower prices, the CS-5, which we introduced to the market in 1978, weighed only 7 kg and cost just 62,000 yen.
Many of the technologies and features of today's Yamaha synths were first realized during the development of compact, affordable instruments such as these. For example, the wheel-type pitch bend and modulation controllers of the CS-15D have become distinctive features of our instruments and are still utilized in the very latest MONTAGE M models. In 1979 we released the CS-20M, switching to digital technology for storing sounds. The CS-70M introduced in 1981 was very similar to modern instruments in terms of functionality: in particular, it offered an auto-tune function that solved the perennial tuning problems encountered in analog synthesizers, and also featured a built-in sequencer realized using a dedicated microprocessor.
The CS01 of 1982 was a truly pivotal synthesizer. Capable of running on batteries and equipped with a mini keyboard, a built-in speaker, and shoulder-strap pins among other features, it ushered in new era in terms of both sound synthesis and mode of use.
Inspired to Create New Forms of Synthesis
Since its beginnings in 1974, synthesizer development at Yamaha has unfolded in parallel with many other advancements in tone generation technologies that also began back in the seventies. Notable examples are research into FM synthesis, which would go on to become extremely popular in the eighties, and the hybrid Pulse Analog Synthesis System (PASS), which combined digital and analog technologies and was adopted for use in Electone tone generators in 1977. Recordings of the sounds produced by these prototype technologies show that, in particular, the analog synthesis approach used in the SY-1 had actually been perfected to a commercially viable level. In this regard, it is remarkable how quickly the Yamaha developers of the time identified so many highly promising new technologies and immediately put them to use.
Even after we released the D-1 as the first Electone, many issues concerning sound quality still needed to be resolved. One particularly challenging problem was how to make these new instruments as expressive as their acoustic counterparts. As we have seen, changes in tone and volume over time were identified as critical in this regard, prompting continuous, round-the-clock research and development in the pursuit of better and better sounds to satisfy this need. Perhaps symbolic of the high-growth period of the Japanese economy, the then president of Yamaha is said to have instructed his team to "spend whatever you want, but give me something that can be the best in the world." With such passion and devotion, synthesizer development at Yamaha during the seventies did more than give birth to a dazzling array of original technologies—it undoubtedly laid the foundations for the coming popularization of the synthesizer as a musical instrument.
