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Modulator LFO

The Modulator LFOs (Low Frequency Oscillator) can be used to create a modulation of property values over time. When added to an RTPC, a Modulator LFO modifies the values of a property between a range of values. Additionally, the values of the LFO properties can be further parameterized or randomized to achieve a high-level of variability.

To diversify the synth for the purpose of the magic_blast_fire_blend element, a Modulator LFO added as an RTPC to each Oscillators PWM (Pulse Wave Modulation) property gives the sound extra "movement" and vibration.

Wwise Synth One PWM (Pulse Width Modulation) properties attached to LFO (settings can be edited in the RTPC tab)
[Note] Designer Note

In Wwise, some properties are additive (Voice Volume, Voice Pitch, and so on...), and some are exclusive. When adding an LFO on the additive properties, the LFO modulation is added to the current value of the property. When adding an LFO on the exclusive properties, the LFO modulation replaces the current value of the property. Properties modified by an LFO are represented by a dashed line ("-") in the Property field.

Wwise Synth One Oscillator 1 showing the effective range of the PWM property modulated by the LFO.

LFOs (Low Frequency Oscillator) are used to create modulation of property values over time. The minimum and maximum RTPC values of the LFO Envelope in the Sound Property Editor affect the base and top of the LFO (nil and peak values). Swapping the min and max values effectively phase reverse the LFO.

Access the Modulator Editor by double-clicking the Modulator LFO in the RTPC dialog or by clicking the [...] button.

Accessing the Modulator Editor by double-clicking the Modulator LFO in the RTPC dialog or by clicking the [...] button.
Modulator LFO Modulator Editor

The properties of the Modulator LFO are:

  • Depth

    • The amplitude variation of the oscillator (in percentage). Maximum amplitude is 1.0.

      • Default value: 100

  • Frequency

    • The number of cycles per second (in Hz).

      • Default value: 1

  • Waveform

    • The shape of the modulator (sine, triangle, square, sawtooth).

      • Default value: Sine

  • Smoothing

    • Low-pass filter over the waveform to smooth hard edges (in percentage).

      • Default value: 0

  • PWM (Pulse Width Modulation)

    • The width of the pulse wave, only applies to the Square waveform (in percentage).

      • Default value: 50

  • Attack

    • The time it takes for the oscillator to reach full amplitude (in seconds).

      • Default value: 0

  • Initial Phase

    • The initial phase of the oscillator waveform (in degrees).

      • Default value: 0

  • Scope

    • Controls how LFOs are created:

      • Voice: An instance of an LFO is created for every voice of the synth when used in MIDI context.

      • Note/ Event: An instance of an LFO is created for every playing instance of the synth when used in MIDI context.

      • Game Object: An instance of LFO is created for each game object instance in relation to the game engine.

      • Global: A single LFO is created for the whole project and used globally by all instances.

    • Default value: Voice

[Note] Designer Note

Additional information for working with LFOs can be found in the Wwise Help Document: Wwise Help > Interacting with the Game > Working with RTPCs > Working with LFOs

Additionally, Frequency Modulation (FM) between the two Oscillators is used to "soften" the sound and helps it blend better with the sample based components of the magic_blast_fire_blend.

Wwise Synth One FM (Frequency Modulation) property

The "FM Amount" property is further modified by an LFO Modulator.

Wwise Synth One FM Amount property RTPC
[Note] Designer Note

LFO objects can be created as Custom or ShareSet. Custom objects are stored in-place, directly inside the object that has it. ShareSets are stored in a separate work-unit and can be re-used across objects.

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