There are two contour generators in the MS20. The first, EG1, is a trapezoid with four stages — Delay, Attack, Sustain (which is always at maximum) and Release — and this is pre-patched simultaneously to the pitches of both oscillators. However, instead of adding the contour voltage to the existing pitch CV, the knob that controls the sweep determines from how far below the played pitch the sweep starts and ends. The second, EG2, generates an HADSR contour, where 'H' is a Hold before the Attack begins. This is pre-patched to the audio VCA, where it acts as you would expect, and to the cutoff frequencies of the filters, where the Sustain level takes the value determined by each of the cutoff frequency knobs. When you press a key, the contour sweeps the filter up from below the programmed cutoff frequency, reaches its zenith some way above it (unless S=10), and then decays back to the Sustain level. When you release the key, the cutoff frequency then drops back down to where it started (unless S=0). Depending upon the position of the Sustain knob and other elements within the patch, all manner of unusual results can be obtained.
