Asynchronous Academy

Envelopes & Articulation (ADSR)

Suggested Duration: 2.5 Hours

"An envelope shapes the lifecycle of a sound; it is how sound breathes."

Synthesizer Design Principle

Envelopes & Articulation (ADSR)

When a violinist draws a bow slowly across a string, the sound starts gradually and lingers. When a guitarist plucks a string, the sound starts instantly and fades away. In music theory, we call this articulation (staccato vs. legato). In synthesis, we use a Volume Envelope (ADSR) to sculpt these shapes over time.

Core Music Theory & Sound Concepts

An envelope shapes how a sound's volume changes from the moment a note is triggered to the moment it is released. It has four stages:

1. Attack (A)

  • How fast the sound reaches its peak volume after a note is triggered.
  • Short Attack: Instantly loud (like a drum or a guitar pluck).
  • Long Attack: Swells in volume slowly (like a violin bow stroke or an ambient pad).

2. Decay (D)

  • How fast the sound drops from its peak volume down to its sustain level.
  • Short Decay: Quickly drops off (creating a dry, percussive click).
  • Long Decay: Slowly slides down to the sustain level.

3. Sustain (S)

  • The volume level the sound holds while the key remains pressed down. Unlike A, D, and R (which are measurements of time), Sustain is a measurement of volume (gain).
  • High Sustain: Note remains loud as long as you hold the key.
  • Zero Sustain: The sound dies out completely even if you hold the key down (like a piano).

4. Release (R)

  • How long the sound takes to fade to complete silence after you let go of the key.
  • Short Release: Audio stops instantly (like stopping a note on a woodwind instrument).
  • Long Release: Audio rings out and echoes (creating a sense of space).

Articulation: Staccato vs. Legato

  • Staccato (Detached/Plucky): Programmed with 0 Attack, Short Decay, 0 Sustain, and Short Release.
  • Legato (Smooth/Connected): Programmed with Long Attack, 0 Decay, Full Sustain, and Long Release.
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Envelope Tip: Try setting the Attack slider to 1000ms. Notice how the notes slowly swell into existence instead of starting with an immediate, sharp edge. This is how synthesizers emulate woodwinds, violins, or ambient backing pads!

Your Assignment Task

  1. Experiment in the Synth Sandbox:
    • The Pluck Patch: Set Attack to 0ms, Decay to 200ms, Sustain to 0%, and Release to 100ms. Play a melody. Note the sharp, percussive staccato feel.
    • The Pad Patch: Set Attack to 1000ms (1 second), Decay to 0ms, Sustain to 100%, and Release to 1500ms (1.5 seconds). Play a note, hold it down, and let go. Observe the slow rise and long fade.
  2. Write and Submit your Reflection:
    • Envelope Mapping: Explain how a snare drum, a church organ, and an acoustic guitar would map onto an ADSR diagram. Which stages are long or short for each?
    • Techno Context: Why is a staccato (short decay, zero sustain) envelope essential for a techno bassline to feel rhythmic rather than muddy?
    • Sandbox Settings: List the exact approximate millisecond values you used in the sandbox to build your favorite sound patch, and describe its texture.
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Envelopes & Articulation Reflection

Submit your completed written comparison and reflection as a Markdown (.md) file using the course app submission portal.

Assessment

Pre-Submission

Before you submit, please complete the Pre-Submission Self-Assessment.

What to Turn In

  • 📤

    ADSR articulation comparison document (Google Doc or Markdown)

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Learning Goals

We are learning to:

  • 🎯

    Differentiate between volume envelopes and analyze their impact on musical articulation.

  • 🎯

    Apply ADSR envelope settings to create staccato and legato musical textures.

Success Criteria

I can:

  • ✅

    Manipulate Attack, Decay, Sustain, and Release controls to alter note behavior.

    Expectations Covered: A1.1, C2.1
  • ✅

    Contrast staccato (plucky) and legato (smooth) settings.

    Expectations Covered: A1.2, C1.2
  • ✅

    Analyze how physical instruments naturally produce envelopes.

    Expectations Covered: C3.1

Rubric

Category Level 4 Level 3 Level 2 Level 1
Knowledge/Understanding
Knowledge of envelope components (ADSR) and traditional articulation terms.
 Demonstrates deep understanding of ADSR settings and articulation mapping. Demonstrates considerable understanding of ADSR settings and articulation. Demonstrates basic understanding of ADSR settings and articulation. Demonstrates limited understanding of ADSR settings and articulation.
Application
Designing distinct textures using envelopes in the sandbox.
 Sound patches are highly distinct, creative, and perfectly model staccato/legato. Sound patches are distinct and correctly model staccato/legato. Sound patches show basic variations in ADSR settings. Sound patches show minimal change or understanding of envelopes.
Knowledge/Understanding
Criteria: Knowledge of envelope components (ADSR) and traditional articulation terms.
Level 4

Demonstrates deep understanding of ADSR settings and articulation mapping.

Level 3

Demonstrates considerable understanding of ADSR settings and articulation.

Level 2

Demonstrates basic understanding of ADSR settings and articulation.

Level 1

Demonstrates limited understanding of ADSR settings and articulation.

Application
Criteria: Designing distinct textures using envelopes in the sandbox.
Level 4

Sound patches are highly distinct, creative, and perfectly model staccato/legato.

Level 3

Sound patches are distinct and correctly model staccato/legato.

Level 2

Sound patches show basic variations in ADSR settings.

Level 1

Sound patches show minimal change or understanding of envelopes.