[1] In the mid-1970s, polyphonic synthesizers had started to emerge, with the releases of the Yamaha GX-1, Oberheim Four Voice, and Polymoog signalling a new direction in synthesis technology.

These instruments, the PE-1000 followed by the PE-2000, offered limited controls and primarily relied on preset sounds.

Although some control over the sound is possible, it operates with a single filter and envelope across all voices and lacks touch sensitivity.

[4] The PE-2000 (Polyphonic Ensemble S) is a string synthesizer, creating a richer sound than the PE-1000 through the use of three oscillators per note, possibly employing delayed and detuned variations of a single oscillator, and a built-in phaser effect.

It includes eight presets, such as organ, brass, chorus, and string sounds, and was utilized by notable artists like Vangelis, Tangerine Dream, Jean-Michel Jarre, and Hawkwind.