KORG Poly-800

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"The Korg Poly-800 is a programmable synthesizer released by Korg in 1983.

Comparable to the Roland Juno and in many ways better, the Poly-800 is an 8 voice polyphonic analog synthesizer with 64 memory patches and up to 50 editable parameters!

There's also a stereo chorus effect, a sequencer, and a weird joystick used to adjust pitch, modulation and the filter.

There is a double mode in which the oscillators double up making 4 fat voices of polyphony.

The Poly-800 could be run off batteries and had guitar strap pegs, allowing a performer to wear it like a guitar.

It is because Poly-800 was only 13 lbs."

Note the Poly-800 shares one filter across all voices, whereas others have one filter per voice. Where this comes into play is when you assign modulation to the filter such as an ENV. Instead of the modulation running independently for each key pressed it is shared across all keys.