LFO

The LFO module provides a standard Low Frequency Oscillator, such as you might find in any conventional synthesizer or sampler. There are one or two unusual features, however.

  • TRIGGER. When the TRIGGER button is activated, the LFO re-triggers (starts again from zero) with each new note. With TRIGGER deactivated, the LFO is free-running.
  • FILE. Clicking the FILE button opens a pop-up menu from which LFO presets can be loaded or saved to files (*.lfo). A collection of useful presets is included (in Alchemy/Libraries/Lfo). You can also ‘Copy’ and ‘Paste’ settings between LFOs, or choose ‘Clear’ to initialise the module.
  • BIPOLAR. When the BIPOLAR button is activated the LFO outputs both negative and positive values in each cycle (from -50% to 50%). With BIPOLAR deactivated, only positive values are output (from 0% to 100%).
  • Current LFO field. Alchemy provides up to 16 LFOs (one by default, more if you create them when assigning modulators — see the Modulation page of this Manual for details). You can access each LFO’s control panel by selecting its number in the Current LFO field.
  • Shape. Click the Shape field to choose an oscillator waveform for the LFO. There are several categories:
    • ‘Basic’ contains the most familiar choices, such as ‘RampUp’, ‘RampDown’, ‘Sine’, ‘Square’, and ‘Triangle’.
    • ‘Basic’ also contains two randomized choices. Use ‘RandGlide’ when you need a constantly fluctuating random modulator; it reaches new random values at a speed set by the Rate control, and it glides smoothly from one value to the next. Use ‘RandHold’ when you need a stepped random modulator (e.g. for ‘sample and hold’ effects); it jumps to new random values at a speed set by the Rate control, holding each value until the next jump occurs.
    • The remaining categories offer more complex shapes; it takes a bit of trial-and-error to learn which shapes are suitable for a particular purpose. The ‘Serial-Angular’ category offers a variety of ‘stepped’ shapes, while the ‘Serial-Smooth’ category provides various complex rising-and-falling patterns. Finally, the ‘UHF’ (ultra-high frequency) category offers shapes containing multiple copies of some pattern, such that the effective modulation speed is a multiple of the speed set by the Rate control.
  • Rate. Controls the LFO rate or frequency. When the Sync button is deactivated, the rate is adjustable over a range of 0 Hz to 220 Hz. With Sync activated, tempo information from the host application is used to calibrate the Rate control in rhythmically meaningful units (i.e. beats and fractions of a beat).
  • Sync. Determines whether the Rate control (see above) is set in Hz (Sync off) or in Beats (Sync on).
  • Delay. When TRIGGER (see above) is activated, Delay introduces a delay between the note-on message and the first cycle of the LFO. The delay is adjustable over a range of 0.00 seconds to 20.00 seconds. When TRIGGER is deactivated, Delay has no effect.
  • Attack. When TRIGGER (see above) is activated, Attack applies an envelope to the LFO’s output, effectively ‘fading it in’, so that the modulation depth steadily increases the longer a note is held. The attack time is adjustable over a range of 0.00 seconds to 20.00 seconds. When TRIGGER is deactivated, Attack has no effect.
  • Phase. When TRIGGER (see above) is activated, Phase allows the starting point of the LFO to be adjusted from ‘zero’ to later in the cycle. The available range is 0.00% to 100.00%.

Note: the LFO module has no depth control. The modulation depth is adjusted using the Depth knob alongside the module’s slot in the modulation rack.