Fourmative Contours consists of four identical envelopes with positive and negative outputs. Each unit has a trigger input for activating the envelope. This is indicated by a green LED. The second and third units can also be triggered manually using the trigger button.

The envelopes can operate independently as attack, hold, or decay curves, depending on the position of the mode switch. A second toggle switch allows the envelope to be set between linear and exponential modes.

The Time potentiometer, combined with the Slow button, controls the envelope speed over a range from 0.5 ms to 37 seconds. This can be further shortened or extended by up to 2.5 hours using a control voltage at the CV input. The audio range can be reached effortlessly, enabling the module to function as an oscillator.

As soon as the envelope completes, a trigger is sent at the End Of Phase output (EOP). This allows the envelope to be transformed into an LFO or to combine multiple units into a complex envelope.

Thanks to the Sum button, subsequent envelopes can be summed, saving the need for a mixer. The Sum input is used to include other CV signals.