4.8 LOW FREQUENCY OSCILLATORS

Low frequency oscillators or LFOs are used to modify synthesis parameters over time. The affected synthesis parameter is called the 'LFO destination'. LFOs, like oscillators, have an output shape and a frequency. LFOs, unlike oscillators, only have a frequency range of around 0-40 Hz. In AXS there are 2 LFOs available for every part.

The picture on the left is LFO1. Click on the shape LEDs to select an LFO output shape. Select an LFO destination by clicking on one of the destination LEDs. The frequency of the LFO can be set using the Rate knob. The amount of modulation caused by the LFO is set using the Amount knob. To force the LFO to restart its shape for every new note, enable LFO sync by clicking on the Sync button.

LFO2 differs from LFO1 on a few points. First of all the available shapes are different. LFO2 has a block-, noise-, trisaw- and sine-shape and a pulsewidth slider to set the pulsewidth or trisaw amount. LFO2 also has some different destinations (Osc2 pulsewidth and Pitch). Selecting the shape, sync, rate, amount and destination works like LFO1. The pulsewidth slider works as OSC1 and OSC2.



Here are some notes and tips on using the LFO:
  • To quickly disable an LFO, set its destination to 'None'.
  • For a wah-wah effect, assign an LFO to 'Filter'. This will modulate the filter cutoff.
  • For a tremelo effect assign an LFO to 'Amplitude'.
  • To modulate the pitch of a single oscillator, assign an LFO to 'Osc1Pitch' or 'Osc2Pitch'. To modulate the pitch of both oscillators, assign LFO2 to 'Pitch'.
  • For exciting strings assign LFOs to Osc1PW and Osc2PW.
  • Selecting 'LFO2 Rate' as LFO1 destination will modulate the frequency of LFO2 around its set value. This is mostly used for soundeffects.