Microfreak/UG/09 Envelope Gen/01 What an Envelope Does

• 09.1 What does an Envelope Generator do?

  • An instrument's envelope and timbre help make it recognizable. An organ reaches full volume at once, stays there while a key is held, then decays quickly. A piano has a slower attack and longer decay. A string section builds and fades more gradually.
  • In electronic music, an envelope can also shape a sound's frequency content. A familiar example is a filter sweep.
  • To hear a filter sweep on the MicroFreak:
    • Set the filter Cutoff to minimum and Resonance to maximum.
    • Set Amp Mod on the Envelope to ON.
    • Set Envelope Attack to 1.7 s, Decay to 7.7 s, Sustain to 90%, and Filter Amount to 70.
  • The filter will sweep through the oscillator's overtones. The effect is stronger with an oscillator rich in harmonics. Try different oscillator models to hear how the filter changes each one.
  • The MicroFreak can use envelopes to shape both a sound's timbre and its amplitude (volume).