User Manual

4.5. LFOs
LFO stands for Low Frequency Oscillator. LFOs generate waveforms in a lower frequency
range than VCOs, and are used as modulation sources to affect other parameters. The
PolyBrute LFOs can run as slowly as one cycle every 50 seconds all the way up to 100Hz
(the audible range). To be "heard" they must be routed to a destination using the Mod Matrix
[p.48].
Each LFO has its own features: LFOs 1 and 2 are very similar, and LFO 3 is in a class by
itself.
4.5.1. LFOs 1 and 2
LFOs 1 and 2 are identical except for one knob in each module: Phase (LFO 1) and Fade In
(LFO 2). Here's what the controls do:
• Phase (LFO 1 only) adjusts where the LFO wave cycle starts relative to the note
trigger. Use the center position to start the LFO at the beginning.
• Fade In (LFO 2 only) offsets the start of LFO 2 and also fades it in gradually.
• Sync locks the LFO to the Seq / Arp tempo (see Sequencer Mode [p.53]), which
can be synced to external sources.
• Rate sets the LFO frequency. An LED in the right corner of each LFO module
flashes to indicate the rate.
• Waveform buttons move left and right through the waveforms. An LED shows the
current choice.
• Mode cycles through three options for the way the LFOs respond to note triggers
and retriggers:
◦ Mono - The LFO oscillates on its own. The wave could be anywhere in
its cycle when a note is triggered, and all notes share the same LFO.
◦ Poly - Each voice has an independent, free-running LFO. If a voice is
retriggered, the LFO does not reset.
◦ Poly>Retrig - Each voice triggers an independent LFO. If the same
voice is retriggered, the LFO resets.
There are seven waveforms available for LFOs 1 and 2: sine, triangle, square, reverse
sawtooth, sawtooth, sample & hold, and slewed random. Their images show what to expect:
the square wave jumps instantly from low to high, the triangle ramps up and back down,
etc. The differences are most obvious at slower rates.
26 Arturia - User Manual PolyBrute - Voice Architecture