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LFO (Low Frequency Oscillator) opcodes are part of the Modulation category of opcodes. They are used to create effects such as pitch vibrato (when modulating pitch), tremolo (when modulating volume) and filter wobble (when modulating filter cutoff)

LFOs are triggered by note-on events for the specified region, which means there are no free-running LFOs in the SFZ spec. If a free-running LFO is needed, for example to apply one slow pitch vibrato wave to a series of rapidly plucked oud notes, that will need to use an external modulation source outside the SFZ player - in other words, perhaps in a DAW that the SFZ player is being used in as a plugin.

SFZ 1 LFOs #

3 LFO destinations in SFZ 1 standard:

  • amplfo (amplitude)
  • fillfo (filter)
  • pitchlfo (pitch)

Here’s a very simple example of a pitch LFO integration

Assignable LFOs (SFZ 2) #

Much like the Flex EG, these newer LFO can target almost any tone-defining parameter:

Here’s a very simple example of an sfz 2 lfo integration, targeted to pitch

Assignable LFO Destinations #

These destinations are added as a suffix to ‘lfoN_’. For example, lfo01_pitch=100 makes LFO 01 affect pitch with a max depth of 100 cents, and lfo03_freq_lfo01=1.3 would make LFO 03 add up to 1.3 Hertz to the frequency of LFO 01. Note that it’s possible to create modulation feedback loops this way, for example LFO 01 modulating LFO 02 while LFO 02 modulates LFO 01.

In addition to the below, in ARIA it’s possible to control the amount of freq_lfo with MIDI CC, so lfo03_freq_lfo01_oncc117 would make LFO 03 add up to 1.3 Hertz to the frequency of LFO 01, with the amount modulated by MIDI CC 117. So, freq_lfo_oncc would be added to the below list for ARIA, though depth_lfo_oncc and depthadd_lfo_oncc do not appear to be available.

  • freq_lfo
  • depth_lfo
  • depthadd_lfo
  • pitch
  • pitch_oncc
  • pitch_smoothcc
  • pitch_stepcc
  • decim
  • decim_oncc
  • decim_smoothcc
  • decim_stepcc
  • bitred
  • bitred_oncc
  • bitred_smoothcc
  • bitred_stepcc
  • cutoff
  • cutoff_oncc
  • cutoff_smoothcc
  • cutoff_stepcc
  • resonance
  • resonance_oncc
  • resonance_smoothcc
  • resonance_stepcc
  • cutoff2
  • cutoff2_oncc
  • cutoff2_smoothcc
  • cutoff2_stepcc
  • resonance2
  • resonance2_oncc
  • resonance2_smoothcc
  • resonance2_stepcc
  • eqNfreq
  • eqNfreq_oncc
  • eqNfreq_smoothcc
  • eqNfreq_stepcc
  • eqNbw
  • eqNbw_oncc
  • eq1bw_smoothcc
  • eqNbw_stepcc
  • eqNgain
  • eqNgain_oncc
  • eqNgain_smoothcc
  • eqNgain_stepcc
  • volume
  • volume_oncc
  • volume_smoothcc
  • volume_stepcc
  • amplitude
  • amplitude_oncc
  • amplitude_smoothcc
  • amplitude_stepcc
  • pan
  • pan_oncc
  • pan_smoothcc
  • pan_stepcc
  • width
  • width_oncc
  • width_smoothcc
  • width_stepcc