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When Effects are inserted on a mixing bus, the mixing stage is always applied at the beginning of the bus processing. Therefore, the multiple inputs of a bus are mixed to a single stream of audio. The positioning transformations are also applied during the mixing stage. Each Effect inserted on the bus is then instantiated only once, and the pre-mixed audio stream feeds the Effect in series. In general, processing costs are proportional to the number of channels.

Note that when a bus is instantiated multiple times, where each instance is associated with a different Game Object, the Effects are instantiated once per bus instance.

The following figure illustrates the internal processing of a mixing bus with Effects:

	Voices are routed to a bus; their signal is sampled when mixing.
	A channel-based format comes from a previous mixing bus.
	A stream of Audio Objects comes from a previous bus Processing Audio Objects.
	All inputs, including voices, channel-based input, and Audio Objects are mixed together.
	A channel-based format is created from the internal mix; no individual Audio Objects remain.
	A channel-based format is operated on by Effects.
	A channel-based format is output by the bus. Note Some Effects can change the output format of a bus, for instance, Audio Objects could be output even though a bus is configured as mono.

Caution

The following Effects are not supported by busses that are Processing Audio Objects: AK Convolution Reverb: Running one instance of the Effect for each Audio Object would cause performance issues. Matrix Reverb: Running one instance of the Effect for each Audio Object would cause performance issues. Peak Limiter: Peak limiting at the Audio Object level would be unreliable. When authoring Audio Objects, use the Mastering Suite plug-in on an Audio Device to apply peak limiting. Recorder: The Recorder cannot run multiple instances. RoomVerb: Running one instance of the Effect for each Audio Object would cause performance issues. Auro Headphone: Not supported. If any of these Effects is inserted on such a bus, it will not be processed at runtime.

When using Effects on a bus with the Processing Audio Objects status, there are a few considerations to be aware of. Unless the Effect is one of the Object Processors, each Effect is instantiated as many times as there are Audio Objects. For example, if a Parametric EQ is inserted on an Audio Objects bus, and 10 Audio Objects are routed to this bus, the Parametric EQ will be instantiated 10 times. In general, processing costs are proportional to the number of Audio Objects routed to the bus.

The following figure illustrates the internal processing of a Processing Audio Objects bus with Effects:

	Voices are routed to a bus; their signal is sampled when mixing.
	A channel-based format comes from a previous mixing bus.
	A stream of Audio Objects comes from a previous bus Processing Audio Objects.
	Any input that is not already an Audio Object, such as voices, and channel-based input, are transformed into individual Audio Objects. These are added to any other Audio Objects supplied to the bus.
	A list of Audio Objects is created.
	Each Audio Object is operated on individually by Effects.
	A list of Audio Objects is output by the bus.

Certain Wwise Effects support Audio Objects intrinsically. Such Effects are called Object Processors and are instantiated only once per bus instance:

Reflect also supports Audio Objects, but in a particular way. While Reflect is often inserted on a mono bus, it can output Audio Objects if the configuration of the parent bus is set to Audio Objects. It then outputs one Audio Object per early reflection. This can represent a substantial number of Audio Objects.