XAUDIO2FX_REVERB_PARAMETERS structure (xaudio2fx.h)

Describes parameters for use in the reverb APO.

Syntax

typedef struct XAUDIO2FX_REVERB_PARAMETERS {
  float  WetDryMix;
  UINT32 ReflectionsDelay;
  BYTE   ReverbDelay;
  BYTE   RearDelay;
  BYTE   SideDelay;
  BYTE   PositionLeft;
  BYTE   PositionRight;
  BYTE   PositionMatrixLeft;
  BYTE   PositionMatrixRight;
  BYTE   EarlyDiffusion;
  BYTE   LateDiffusion;
  BYTE   LowEQGain;
  BYTE   LowEQCutoff;
  BYTE   HighEQGain;
  BYTE   HighEQCutoff;
  float  RoomFilterFreq;
  float  RoomFilterMain;
  float  RoomFilterHF;
  float  ReflectionsGain;
  float  ReverbGain;
  float  DecayTime;
  float  Density;
  float  RoomSize;
  BOOL   DisableLateField;
} XAUDIO2FX_REVERB_PARAMETERS;

Members

WetDryMix

Percentage of the output that will be reverb. Allowable values are from 0 to 100.

ReflectionsDelay

The delay time of the first reflection relative to the direct path. Permitted range is from 0 to 300 milliseconds.

ReverbDelay

Delay of reverb relative to the first reflection. Permitted range is from 0 to 85 milliseconds.

RearDelay

Delay for the left rear output and right rear output. Permitted range is from 0 to 5 milliseconds.

SideDelay

Delay for the left side output and right side output. Permitted range is from 0 to 5 milliseconds.

PositionLeft

Position of the left input within the simulated space relative to the listener. With PositionLeft set to the minimum value, the left input is placed close to the listener. In this position, early reflections are dominant, and the reverb decay is set back in the sound field and reduced in amplitude. With PositionLeft set to the maximum value, the left input is placed at a maximum distance from the listener within the simulated room. PositionLeft does not affect the reverb decay time (liveness of the room), only the apparent position of the source relative to the listener. Permitted range is from 0 to 30 (no units).

PositionRight

Same as PositionLeft, but affecting only the right input. Permitted range is from 0 to 30 (no units).

PositionMatrixLeft

Gives a greater or lesser impression of distance from the source to the listener. Permitted range is from 0 to 30 (no units).

PositionMatrixRight

Gives a greater or lesser impression of distance from the source to the listener. Permitted range is from 0 to 30 (no units).

EarlyDiffusion

Controls the character of the individual wall reflections. Set to minimum value to simulate a hard flat surface and to maximum value to simulate a diffuse surface. Permitted range is from 0 to 15 (no units).

LateDiffusion

Controls the character of the individual wall reverberations. Set to minimum value to simulate a hard flat surface and to maximum value to simulate a diffuse surface. Permitted range is from 0 to 15 (no units).

LowEQGain

Adjusts the decay time of low frequencies relative to the decay time at 1 kHz. The values correspond to dB of gain as follows:

Value	0	1	2	3	4	5	6	7	8	9	10	11	12
Gain (dB)	-8	-7	-6	-5	-4	-3	-2	-1	0	+1	+2	+3	+4

  Permitted range is from 0 to 12 (no units).

LowEQCutoff

Sets the corner frequency of the low pass filter that is controlled by the LowEQGain parameter. The values correspond to frequency in Hz as follows:

Value	0	1	2	3	4	5	6	7	8	9
Frequency (Hz)	50	100	150	200	250	300	350	400	450	500

 

Permitted range is from 0 to 9 (no units).

HighEQGain

Adjusts the decay time of high frequencies relative to the decay time at 1 kHz. When set to zero, high frequencies decay at the same rate as 1 kHz. When set to maximum value, high frequencies decay at a much faster rate than 1 kHz.

Value	0	1	2	3	4	5	6	7	8
Gain (dB)	-8	-7	-6	-5	-4	-3	-2	-1	0

 

Permitted range is from 0 to 8 (no units).

HighEQCutoff

Sets the corner frequency of the high pass filter that is controlled by the HighEQGain parameter. The values correspond to frequency in kHz as follows:

Value	0	1	2	3	4	5	6	7	8	9	10	11	12	13	14
Frequency (kHz)	1	1.5	2	2.5	3	3.5	4	4.5	5	5.5	6	6.5	7	7.5	8

 

Permitted range is from 0 to 14 (no units).

RoomFilterFreq

Sets the corner frequency of the low pass filter for the room effect. Permitted range is from 20 to 20,000 Hz.

RoomFilterMain

Sets the pass band intensity level of the low-pass filter for both the early reflections and the late field reverberation. Permitted range is from -100 to 0 dB.

RoomFilterHF

Sets the intensity of the low-pass filter for both the early reflections and the late field reverberation at the corner frequency (RoomFilterFreq). Permitted range is from -100 to 0 dB.

ReflectionsGain

Adjusts the intensity of the early reflections. Permitted range is from -100 to 20 dB.

ReverbGain

Adjusts the intensity of the reverberations. Permitted range is from -100 to 20 dB.

DecayTime

Reverberation decay time at 1 kHz. This is the time that a full scale input signal decays by 60 dB. Permitted range is from 0.1 to infinity seconds.

Density

Controls the modal density in the late field reverberation. For colorless spaces, Density should be set to the maximum value (100). As Density is decreased, the sound becomes hollow (comb filtered). This is an effect that can be useful if you are trying to model a silo. Permitted range as a percentage is from 0 to 100.

RoomSize

The apparent size of the acoustic space. Permitted range is from 1 to 100 feet.

DisableLateField

If set to TRUE, disables late field reflection calculations. Disabling late field reflection calculations results in a significant CPU time savings.

Remarks

All parameters related to sampling rate or time are relative to a 48kHz voice and must be scaled for use with other sampling rates. For example, setting ReflectionsDelay to 300ms gives a true 300ms delay when the reverb is hosted in a 48kHz voice, but becomes a 150ms delay when hosted in a 24kHz voice.

Platform Requirements

Windows 10 (XAudio2.9); Windows 8, Windows Phone 8 (XAudio 2.8); DirectX SDK (XAudio 2.7)

Requirements

Requirement	Value
Header	xaudio2fx.h

See also

How to: Create an Effect Chain

IXAudio2Voice::SetEffectParameters

XAPO Overview

XAudio Structures

XAudio2CreateReverb