Microfreak/UG/08 LFO

• 08 The LFO

  • An LFO (short for low-frequency oscillator) produces waveforms at sub-audio frequencies. These waveforms can modulate other parts of the MicroFreak, such as:
    • The oscillator pitch
    • The filter cutoff frequency
    • The filter emphasis
    • The stages of an envelope
  • A familiar use for LFO modulation is a filter sweep: the LFO waveform moves the cutoff point of a low-pass filter over time.
  • The MicroFreak LFO
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  • Try the triangle and rising sawtooth waves to hear how the sweep changes shape. The rectangle wave cycles between low and high states, making it useful for toggling an oscillator between two pitches. Depending on the Matrix modulation amount, the pitch can jump by two or four scale steps, or by a full octave.
  • Microfreak/UG/08 LFO/01 LFO Shape

    • 08.1 LFO Shape

      • The Shape button selects one of six waveforms: sine, triangle, rising sawtooth, rectangle (square), random (sample and hold), or random gliding (smoothed random).

      • Note/Info The square wave has a 50% duty cycle: it stays high for half of each cycle.
        

      • The Random wave creates random modulations. For a familiar science-fiction computer sound, select Random, set the LFO speed to about 4 Hz, choose the LFO-to-Pitch crossing in the Matrix, then set the modulation amount to about 30.
      • Random gliding is a slewed random wave. Its pitch changes gradually between random values, unlike the abrupt changes of the Random wave. Routing it to oscillator pitch makes the modulation amount easier to fine-tune before applying it to another target.

      • Note/Info Matrix modulation on the MicroFreak is bipolar: it can affect a target in both positive and negative directions. This offers more sound-design options, though a slow negative modulation of the Analog Filter can make the sound inaudible for part of the cycle.
        

  • Microfreak/UG/08 LFO/02 LFO Rate

    • 08.2 LFO Rate

      • The Rate knob sets the LFO speed from 0.06 Hz to 100 Hz.
      • The LFO does not follow the MicroFreak clock by default. Press the Rate encoder to enable Sync.
      • With Sync off, the display shows the rate in hertz. With Sync on, the LFO follows the MicroFreak clock, a DAW clock, or an external MIDI clock, and the display shows divisions from 8/1 to 1/32: 8/1, 4/1, 2/1, 1/1, 1/2, 1/2t, 1/4, 1/4t, 1/8, 1/8t, 1/16, 1/16t, and 1/32.
      • The displayed ratio sets how the LFO cycle relates to the clock. At 8/1, the slowest rate, a cycle completes in eight pulses. Each step up doubles the LFO speed, except the 1/2t, 1/4t, and 1/8t triplet settings. At 1/4, one LFO cycle equals a quarter note.
      • Matching the LFO rate to the MicroFreak sequencer, a DAW, or another clock source can create rhythms at multiples or divisions of the clock.

      • Note/Info The display shows the LFO sync ratio.
        

      • Turning Sync off uncouples the LFO from the MicroFreak tempo and restores its 0.06 Hz to 100 Hz range.
      • Microfreak/UG/08 LFO/02 LFO Rate/01 LFO Retriggering

        • 08.2.1 LFO Retriggering

          • LFO retriggering restarts the LFO each time you press a keyboard key or the arpeggiator or sequencer generates a gate signal. This can make the LFO add a small pitch rise at the start of each note.
          • To enable retriggering, open Utility and set Preset > LFO Retrig to ON.
  • Microfreak/UG/08 LFO/03 Freaky Tips

    • 08.3 Freaky Tips and Tricks

      • Use the LFO to modulate both the filter cutoff and the envelope attack and decay times. Filter cutoff is a standard Matrix connection; assign the envelope attack and decay destinations explicitly in the Matrix. See Microfreak/UG/05 Connections/02 Matrix and Encoder for details.
      • Adding some randomness to filter cutoff creates a fuzzy effect. Random modulation of an envelope's decay or sustain adds variety to a rhythmic pulse and can revive a stale sound.
      • Use the sine or sawtooth wave to modulate an envelope's level. Playing an arpeggio then produces cyclic crescendos and diminuendos. A very slow LFO can also modulate the Cycling Envelope's rise and fall times; route the resulting envelope to other destinations.
      • Use the rising sawtooth to modulate the decay time of the Standard or Cycling Envelope for more realistic drum or bell sounds. The Cycling Envelope's attack and fall shapes can also change dynamically from linear to exponential. See Microfreak/UG/09 Envelope Gen for details.
      • To animate a sequence or arpeggio, sync the LFO, select Random, and apply a small amount of modulation to oscillator pitch in the Matrix. Modulate the Matrix amount with a very short Cycling Envelope set to ENV, so the LFO modulation ends after the initial attack.
      • Assign Glide amount as an LFO destination to switch Glide on and off by setting its amount to zero. With Sync on, the LFO can activate Glide every other or every fourth sequencer step.