Envelopes require a trigger to fire; LFOs cycle continuously without intervention — both share rise and fall stages

The defining difference between an envelope and an LFO is their trigger relationship. Envelopes are event-driven: they wait for a gate or trigger signal (from a keyboard, sequencer, or patch point) before running their rise/fall trajectory. LFOs are autonomous: once running they cycle indefinitely, requiring no external input to sustain. Despite this operational difference, both produce modulation by moving voltage through ascending and descending portions. An envelope’s attack is a rise; its decay/release is a fall. An LFO’s positive slope is a rise; its negative slope is a fall. This shared structure means the same hardware (MATHS channels 1 and 4) can serve as either, depending only on whether cycle mode is enabled.

Examples

Envelope: gate in → rise (attack) → fall (decay/release). LFO: cycle button on → autonomous rise → fall, repeating. MATHS channel 1 in cycle mode = LFO; with trigger in = envelope.

Assessment

Explain what makes an LFO different from an envelope at the signal-generation level. Then demonstrate how one hardware circuit (like MATHS) can operate as either.