Working with LFOs

LFOs (Low Frequency Oscillator) are used to create modulation of property values over time. The properties of the LFO are:

Property	Description
Depth	The amplitude variation of the oscillator (in percentage)
Frequency	The number of cycles per second (in Hz)
Waveform	The shape of the modulator
Smoothing	Low-pass filter over the waveform to smooth hard edges (in percentage)
PWM (Pulse Width Modulation)	The width of the pulse wave, only applies to the Square waveform (in percentage)
Attack	The time it takes for the oscillator to reach full amplitude (in seconds)
Initial Phase	The initial phase of the oscillator waveform (in degrees)
Scope	Define how LFO instances are created: Voice: An instance of LFO is created for every sound/object playback. Note/Event: An instance of LFO is created for every playing instance, or note when used in MIDI context. Game Object: An instance of LFO is created for each game object. Global: A single LFO is created for the whole project.

In Wwise, some properties are additive (Voice Volume, Voice Pitch, etc...), 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 replace the current value of the property.

To modulate the Voice Volume with a LFO:

In the Project Explorer, select an object to add LFO.
In the Property Editor, go to the RTPC tab.
In the RTPC list, click the [>>] button.
From the selector menu, select Voice Volume.
Click the X-axis selector button.
From the selector menu, select LFO > Default (Custom).
Click the [...] button to edit the LFO properties.
Edit the curve to set the range of modulation.

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.

	Caution
	A modulator's processing time depends on its RTPC usage. For most properties, a modulator is evaluated once per audio frame. However, for the property voice volume, the associated modulator is evaluated at every frame. Use modulators selectively as they can consume a significant amount of memory and CPU.

	Note
	The RTPC cursors for Modulators, both LFO and Envelope, do not tell you their specific values at any point in time since they are determined by the modulator's internal properties.

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