Much of the voltage-controller filter and voltage controlled amplifier sections were based on previous analog mono-synths from Roland.
Sliders adjust the VCO, VCF, VCA, and LFO sections; there is no memory to store settings.
Polyensemble: this is not a true synthesizer section, but rather a unique distortion circuit using custom Roland "trigger pulse generator" chips.
The pitch detection circuit makes use of another proprietary Roland part: the "fundamental generator" chip.
In addition to the same ADS Envelope Generator found in the Polyensemble and Bass, there is a triangle wave LFO to modulate pulse width or the filter cutoff.
Later versions added an extra oscillator so that the Solo Melody section could be detuned from the rest of the synthesizer, resulting in a richer, "fatter" sound.
The most effective use of the GR-500 may be found in the Polyensemble section, which, when combined with the infinite sustain system, made for a rich, symphonic sound.