Sampler LFO overview in Logic Pro for Mac

You can use any of the four identical LFOs (low frequency oscillators) shown in the Modulators pane to control and add animation to your instruments. All LFOs are available as sources and targets in the Mod Matrix pane. If you’re new to synthesizers and the concept behind LFOs, see Common modulation sources.

You can use all Sampler LFOs polyphonically or monophonically. When used polyphonically, this means that modulation of multiple voices is not phase-locked. The LFOs can also be key-synced—each time you play a key, LFO modulation of this voice is started from zero.

To understand the non-phase-locked characteristic more fully, imagine playing a chord on your keyboard. If an LFO is used to modulate pitch, for example, the pitch of one voice might rise, the pitch of another voice might fall, and the pitch of a third voice might reach its minimum value. As you can see, the modulation is independent for each voice, or note you play.

When you use LFOs monophonically, modulation is identical for all voices. For example, imagine a chord you are playing on the keyboard is using LFO 2 to modulate pitch, which you set up in the Mod Matrix. In this situation, the pitch of all voices in your played chord rise and fall synchronously.

The key-sync feature ensures that the LFO waveform cycle always starts from zero, which results in consistent modulation of each voice you play. If LFO waveform cycles are not synchronized in this way, individual note modulations are uneven.

You can set all LFOs to either oscillate freely or to be synchronized with the Logic Pro tempo, in values ranging between 32 bars and 1/128th triplets.

You can fade LFOs in or out automatically with the built-in ramp generator available in each LFO.

LFO parameters

Double-click a parameter value field to enter a new value. Press Return to complete the operation.

Minus button (—): Highlight the modulator you want to remove, then click the button to delete the modulator from the Modulators pane.
+ LFO button: Add an LFO to the Modulators pane. Up to four LFOs can be used.
Waveform pop-up menu: Choose the LFO waveform. For details about how to use them, see Sampler LFO waveforms.
Sync button: Turn on to synchronize the LFO with the project tempo. The note icon is illuminated when active.
Rate field: Use to set the frequency, or speed, of LFO modulation. The value is shown in note values when the Sync button is active. See Set the Sampler LFO rate.
Fade field: Use to set the time it takes for LFO modulation to fade in or fade out, depending on which Fade button is active. See Use the Sampler LFO ramp generator.
Fade In or Fade Out button: Click to set an LFO fade-in or fade-out. Use the Fade field to set the fade duration.
Waveform display: Shows the current LFO waveform. Drag horizontally to set the frequency, or speed, of LFO modulation.
Phase field: Drag vertically to offset the waveform start point.
Mono or Poly button: Set the LFO to run monophonically or polyphonically. Mono results in identical modulation of all voices. Poly provides independent modulation of each voice.
Unipolar or Bipolar button: Run the LFO waveform in one pole (positive) or two pole (positive and negative) mode.
Key Trigger button: Turn on key sync for the LFO. Each time you play a key, the LFO waveform is restarted from the start point.

Download the guides:

Logic Pro User Guide: PDF

Logic Pro Instruments: PDF

Logic Pro Effects: PDF

Control Surfaces Support Guide: PDF

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Logic Pro User Guide for Mac

Sampler LFO overview in Logic Pro for Mac

LFO parameters