Understanding one of the most important CV sources in Eurorack
If CV, Gate, and Trigger are the language of Eurorack, then envelopes are how that language becomes musical.
Envelopes shape how sounds start, evolve, and stop over time. They control dynamics, articulation, and movement, and they’re essential for everything from punchy basslines to evolving ambient textures.
In this post, we’ll break down what envelopes are, how they work, and the most common envelope types you’ll encounter in Eurorack.
What Is an Envelope?
An envelope is a CV signal that changes over time in response to a gate or trigger.
Instead of a static voltage, an envelope outputs a shape—a rise and/or fall in voltage—that you can use to control other modules.
Most commonly, envelopes are used to control:
- Amplitude (via a VCA)
- Filter cutoff
- Pitch modulation
- Waveshaping or timbre parameters
- Any destination that accepts CV
Envelopes tell a sound how to happen.
How Envelopes Are Triggered
Gate-triggered envelopes start when a gate goes high and can remain active as long as the gate stays high. They are common in keyboard and sequencer patches.
Trigger-triggered envelopes fire once and run their full course regardless of signal length. They are common in percussion and one-shot sounds.
ADSR Envelopes
Attack: How fast the envelope rises from zero to its maximum.
Decay: How long it takes to fall from the maximum level to the sustain level.
Sustain: The level held while the gate remains high.
Release: How long it takes to return to zero after the gate ends.
Typical uses include expressive leads, basses, and keyboard-style patches.
AR and AD Envelopes
AR envelopes consist of attack and release stages and follow the length of the incoming gate.
AD envelopes are trigger-based, have no sustain stage, and always run their full course.
These simpler envelopes are extremely common and useful in Eurorack.
Envelope Shapes
Linear shapes change evenly.
Exponential shapes feel punchy and natural for volume.
Logarithmic shapes rise slowly and fall quickly.
Envelope shape has a major impact on the feel of a patch.
Advanced Envelope Features
Looping envelopes can act like LFOs.
Voltage-controlled envelopes like GGS 3310 VC-ADSR allow dynamic modulation of envelope stages.
Multi-stage envelopes provide complex evolving shapes.
End-of-cycle outputs enable event chaining and generative patching.
Common Beginner Mistakes
Using envelopes without a VCA.
Expecting sustain to work with triggers.
Ignoring envelope shape.
Not attenuating envelope CV.
Key Takeaways
Envelopes output CV over time.
ADSR is great for expressive sounds.
AD and AR envelopes are simpler and flexible.
Envelope shape and triggering method matter.
Envelopes can be used far beyond volume control.