The Yamaha CS80 was
the world's first truly polyphonic, 'commercially available' analogue
synthesiser. ARP had already released their Omni polysynth. However,
this used organ technology to provide the polyphony and all voices
shared a common filter and envelope so it wasn't truly polyphonic
in the strict sense of the word. The CS80 changed all this.
Released in 1977, the CS80 pre-dated
the Prophet 5 by a year and the Oberheim OB-X by several years offering
8-voice polyphony with a 61-note weighted keyboard, polyphonic aftertouch
and other performance controls. It was actually an off-shoot of
Yamaha's prohibitively expensive ($60,000) flagship GX1 but even
at a 'mere' $7,000, the CS80 was still beyond the reach of most
In itself, each voice was unremarkable....
a single VCO into a LPF into an HPF and into the final VCA with
ADSR envelopes and LFOs for vibrato, filter sweeps and PWM except....
There were two of these per voice.
That's right... rather than using the 'standard' two-oscillators
into a lowpass filter into VCA architecture that was common on most
monosynths at the time (and which was to be adopted as the standard
voice architecture by polysynths in later years), the CS80 had two
totally separate synths on each of its eight voices so that, in
effect, you were playing 2 x 8-voice synths from the keyboard. These
could be set to produce different sounds making it possible to layer
sounds effortlessly. Alternatively, both synths could be set to
produce the same sound for big detuned textures.
The oscillator produced the standard sawtooth and square
waveforms (simultaneously) but unusually, it also produced a sine
wave which could be mixed in at the final VCA to add weight to the
sound. PWM was possible and each oscillator had its own separate
LFO for the purpose. There was also a noise generator with its own
The filters were resonant lowpass and highpass (12dB/Octave)
which could be used independently or together as a bandpass filter.
The filters have their own dedicated envelope but this was not the
conventional ADSR type. Instead, it was ADR with curious 'INITIAL
LEVEL' and 'ATTACK LEVEL' controls that not only set the start level
of the envelope but could also be used to set sustain level... mmm...
very confusing! The VCA was simpler having level controls for the
filter output and the oscillator sinewave and a normal ADSR envelope.
Each synth had controls to set their response to velocity and aftertouch.
What made the CS80 totally unique, however, was its performance
controls which arguably remain unsurpassed even today!
The weighted keyboard's velocity could control amplitude,
filter cutoff and a special pitch envelope whilst the keyboard's
totally polyphonic aftertouch could control amplitude, filter cutoff,
the pulse width LFO and the main LFO's speed and depth. Polyphonic
aftertouch is something that has to be used to be believed. Basically,
the aftertouch is available independently for each voice so you
can hold down a chord and swell just one note in by pressing harder
on one key (unlike conventional aftertouch where doing the same
would affect all voices equally). One of the CS80's most famous
users, Vangelis, used this to great effect in his music and you
can hear it all over the sound track he wrote for the film Blade
Runner and is a trademark sound in much of his music.
Furthermore, just above the keyboard were easily accessible
master controls for brightness, resonance and tuning plus controls
that governed velocity and aftertouch sensitivity. There was also
a master LFO that offered a wide range of waveforms over a very
wide frequency range. These affected both synth layers equally.
There were also controls to set the octave for each layer plus a
balance control to set the levels between the two synth layers and
a separate control to detune the two synth layers. There were also
controls to set the tonal balance across the keyboard range (BRILLIANCE)
and also balance levels across the top and bottom of the keyboard.
There was also a ring modulator but instead of ring modulating
the two synth sections as you might expect, it had its own modulating
oscillator with an envelope that controlled that oscillator's pitch
- thus the whole synth was processed through this unusual ring modulator
for everything from subtle tremolo to out-and-out filthy clangs!
Unique to the CS80 was also its ribbon controller. Located
just above the keyboard, this could be used for pitch bend sweeps
of outrageous proportions. Unlike other ribbon controllers that
have a fixed 'centre point', the CS80's uses the position you place
your finger on first as the centre point - by pressing the top of
the controller and sliding down, you have a pitch bend range that
goes sub-sonic! Such was the length and range of the ribbon controller,
it could almost be used as an Ondes Martenot or Theremin and with
practice, you could play tunes on it!
To the left of the keyboard was a panel that housed further
controls for sustain plus tremolo and chorus effects. It also housed
controls for portamento and glissando (quantized portamento that
moves in steps - unique at the time and still uncommon today).