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# Audio Unit Properties

Obtain information about the built-in mixers, equalizers, filters, effects, and other Audio Unit app extensions.

## Topics

### General

[Other Plug-In Formats](/documentation/AudioToolbox/1534082-other-plug-in-formats)

[RenderQuality](/documentation/AudioToolbox/1534177-renderquality)

Render quality settings for audio units.

[General Audio Unit Properties](/documentation/AudioToolbox/general-audio-unit-properties)

Properties that apply to any audio unit.

[`HostCallbackInfo`](/documentation/AudioToolbox/HostCallbackInfo)

The time- and transport-related callback functions for an audio unit.

### Mixers

[Audio Unit Mixer Subtypes](/documentation/AudioToolbox/1584146-audio-unit-mixer-subtypes)

[`AUSpatialMixerAttenuationCurve`](/documentation/AudioToolbox/AUSpatialMixerAttenuationCurve)

[`AUSpatialMixerRenderingFlags`](/documentation/AudioToolbox/AUSpatialMixerRenderingFlags)

[AUSpatialMixer Parameters](/documentation/AudioToolbox/1390073-auspatialmixer-parameters)

[Panner Audio Unit Parameters](/documentation/AudioToolbox/1389991-panner-audio-unit-parameters)

[AUMatrixMixer Parameters](/documentation/AudioToolbox/1390003-aumatrixmixer-parameters)

[AUMultiChannelMixer Parameters](/documentation/AudioToolbox/1389739-aumultichannelmixer_parameters)

Parameters for the Multichannel Mixer unit.

[Spatial Mixer Property IDs](/documentation/AudioToolbox/1534150-spatial-mixer-property-ids)

[Stereo Mixer Unit Parameters](/documentation/AudioToolbox/1389928-stereo-mixer-unit-parameters)

[Mixer Audio Unit Properties](/documentation/AudioToolbox/1534041-mixer_audio_unit_properties)

Properties for Apple mixer audio units.

[Mixer Audio Unit Subtypes](/documentation/AudioToolbox/1584150-mixer_audio_unit_subtypes)

Audio mixing audio unit subtypes for audio units provided by Apple.

[`AUSpatialMixerOutputType`](/documentation/AudioToolbox/AUSpatialMixerOutputType)

[`AUSpatialMixerPointSourceInHeadMode`](/documentation/AudioToolbox/AUSpatialMixerPointSourceInHeadMode)

[`AUSpatialMixerSourceMode`](/documentation/AudioToolbox/AUSpatialMixerSourceMode)

[3D Mixer Unit Parameters](/documentation/AudioToolbox/1389763-3d_mixer_unit_parameters)

Parameters for the 3D Mixer unit.

[`AU3DMixerAttenuationCurve`](/documentation/AudioToolbox/AU3DMixerAttenuationCurve)

[`AU3DMixerRenderingFlags`](/documentation/AudioToolbox/AU3DMixerRenderingFlags)

[`MixerDistanceParams`](/documentation/AudioToolbox/MixerDistanceParams)

### Equalizers

[Parametric EQ Unit Parameters](/documentation/AudioToolbox/1389950-parametric_eq_unit_parameters)

Parameters for the Parametric EQ unit.

[Audio Unit Graphic EQ Parameter ID](/documentation/AudioToolbox/1389932-audio-unit-graphic-eq-parameter)

[Peak Limiter Unit Parameters](/documentation/AudioToolbox/1389597-peak_limiter_unit_parameters)

Parameters for the Peak Limiter unit.

[Dynamics Processor Unit Parameters](/documentation/AudioToolbox/1389787-dynamics_processor_unit_paramete)

Parameters for the Dynamics Processor unit.

[Frequency Response Constants](/documentation/AudioToolbox/1534092-frequency_response_constants)

The maximum number of frequency response bin structures for the `AudioUnitProperty_FrequencyResponse` property.

[`AUSpatializationAlgorithm`](/documentation/AudioToolbox/AUSpatializationAlgorithm)

### Filters

[Audio Unit Filter Subtypes](/documentation/AudioToolbox/1584153-audio-unit-filter-subtypes)

[Bandpass Unit Parameters](/documentation/AudioToolbox/1390144-bandpass_unit_parameters)

Parameters for the Bandpass unit.

[AUHipass Parameters](/documentation/AudioToolbox/1389948-auhipass_parameters)

Parameters for the Highpass unit.

[AULowpass Parameters](/documentation/AudioToolbox/1389999-aulowpass_parameters)

Parameters for the Lowpass unit.

[AULowShelf Parameters](/documentation/AudioToolbox/1389995-aulowshelf_parameters)

Parameters for the Low Shelf Filter unit.

[AUHighShelfFilter Parameters](/documentation/AudioToolbox/1389967-auhighshelffilter_parameters)

Parameters for the High Shelf Filter unit.

[AUNBandEQ Filter Types](/documentation/AudioToolbox/1389965-aunbandeq_filter_types)

Values for the filter type parameter of the Multitype EQ (NBandEQ) unit.

[AUNBandEQ Property IDs](/documentation/AudioToolbox/1534022-aunbandeq-property-ids)

[AUNBandEQ Parameters](/documentation/AudioToolbox/1389745-aunbandeq-parameters)

### Effects

[Effect Audio Unit Subtypes](/documentation/AudioToolbox/1584154-effect_audio_unit_subtypes)

Effect (digital signal processing) audio unit subtypes for audio units provided by Apple.

[AUMatrixReverb Parameters](/documentation/AudioToolbox/1389801-aumatrixreverb-parameters)

[AUDistortion Parameters](/documentation/AudioToolbox/1390086-audistortion-parameters)

[Reverb Parameters](/documentation/AudioToolbox/1390119-reverb_parameters)

Additional reverb parameters.

[Reverb Unit Parameters](/documentation/AudioToolbox/1615024-reverb_unit_parameters)

Parameters for the Reverb unit.

[`AUReverbRoomType`](/documentation/AudioToolbox/AUReverbRoomType)

[Varispeed Unit Parameters](/documentation/AudioToolbox/1390014-varispeed_unit_parameters)

Parameters for the Varispeed unit.

[AUDelay Parameters](/documentation/AudioToolbox/1390010-audelay-parameters)

[AUMultibandCompressor Parameters](/documentation/AudioToolbox/1389781-aumultibandcompressor-parameters)

[AUDeferredRenderer Properties](/documentation/AudioToolbox/1534061-audeferredrenderer-properties)

[AUSampleDelay Parameters](/documentation/AudioToolbox/3547050-ausampledelay-parameters)

[AUNewTimePitch Parameters](/documentation/AudioToolbox/1389643-aunewtimepitch-parameters)

[AUTimePitch, AUTimePitch (offline), and AUPitch Unit Parameters](/documentation/AudioToolbox/1389946-autimepitch_autimepitch_offline)

### Input/Output

[I/O Audio Unit Properties](/documentation/AudioToolbox/1534116-i_o_audio_unit_properties)

Properties for Apple I/O audio units (sometimes called output units).

[Inter-App Output Unit Property IDs](/documentation/AudioToolbox/1621039-inter-app-output-unit-property-ids)

[Inter-App Audio Unit Property IDs](/documentation/AudioToolbox/1621038-inter-app-audio-unit-property-ids)

[Output Unit Parameters](/documentation/AudioToolbox/1389916-output_unit_parameters)

[AUNetReceive Properties](/documentation/AudioToolbox/1534109-aunetreceive-properties)

[AUNetSend Properties](/documentation/AudioToolbox/1534207-aunetsend-properties)

[AUNetSend Parameters](/documentation/AudioToolbox/1389633-aunetsend-parameters)

[AUNetReceive Parameters](/documentation/AudioToolbox/1389920-aunetreceive-parameters)

[AUNetSendPresetFormat Properties](/documentation/AudioToolbox/1534212-aunetsendpresetformat-properties)

[Net Status Audio Unit Parameters](/documentation/AudioToolbox/1389891-net-status-audio-unit-parameters)

[I/O Audio Unit Function Selectors](/documentation/AudioToolbox/1585807-i_o_audio_unit_function_selector)

Audio unit component selectors, specific to I/O audio units, that correspond to functions in the audio unit API.

[`AudioOutputUnitMIDICallbacks`](/documentation/AudioToolbox/AudioOutputUnitMIDICallbacks)

[`AudioOutputUnitStartAtTimeParams`](/documentation/AudioToolbox/AudioOutputUnitStartAtTimeParams)

A timestamp for scheduled starting of an I/O audio unit.

### Generators

[AURandom Parameters](/documentation/AudioToolbox/1389639-aurandom-parameters)

[AUSampler Parameters](/documentation/AudioToolbox/1389769-ausampler-parameters)

[AUSampler Property IDs](/documentation/AudioToolbox/1534086-ausampler-property-ids)

[AUSampler Properties](/documentation/AudioToolbox/1533959-ausampler-properties)

[AURogerBeep Parameters](/documentation/AudioToolbox/1389727-aurogerbeep-parameters)

[AUMIDISynth Properties](/documentation/AudioToolbox/1534190-aumidisynth-properties)

[AURoundTripAACParam Parameters](/documentation/AudioToolbox/1389808-auroundtripaacparam-parameters)


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