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(8.D.2.2 ) DelayMixerSmoothed

Owned by Catherine Spain
Oct 06, 2023
5 min read

Overview

A smoothed mixer module with M outputs and N inputs

Discussion

This implements the same functionality as MultiChannelMixerSmoothed module, but is significantly more efficient, both in speed and memory.

This time delay module has multiple input and multiple output channels with real data only. Smoothed delay can be applied at each intersections of the input and output lines. The delays and gains to be applied at each intersection comes from the control pin in interleaved order gainIn1Out1, delayIn1Out1, gainIn2Out1, delayIn2Out1 and so on. Delays are specified in milliseconds and are in the range of [0 MAXDELAY].

At construction time, you specify the maximum delay (maxDelay) of the module. The variable, maxDelay determines the size of the internal state buffer. The size of the internal state buffer equals (maxDelay+1)*numChannels samples. The module applies smooth cross fading when delay or gain values are changed at run-time.

When the module is bypassed, it copies the ith input channel to the ith output channel. If the module has more output channels than input channels, the remaining output channels are set to 0.

Type Definition

typedef struct _ModuleDelayMixerSmoothed { ModuleInstanceDescriptor instance; // Common Audio Weaver module instance structure FLOAT32 maxDelayTime; // Maximum delay, in milliseconds. FLOAT32 smoothingTimeDelay; // Time constant of the cross fading process of delay FLOAT32 smoothingTimeGain; // Time constant of the cross fading process of gain FLOAT32 smoothingCoeff; // Smoothing coefficient for cross fading of delays. FLOAT32 smoothingCoeffGain; // Smoothing coefficient for cross fading of gains. INT32 stateHeap; // Heap in which to allocate memory. INT32 maxDelay; // Max delay in samples. INT32* prevDelay; // Array holding previous delay values. INT32* currentDelay; // Array holding current delay values. FLOAT32* prevGain; // Array holding previous gain values. FLOAT32* currentGain; // Array holding current gain values. FLOAT32* oldGain; // Gain parameter for cross fading of delay. FLOAT32* newGain; // Gain parameter for cross fading of delay. INT32* fadingDone; // State variable to implement cross fading of delay. INT32* stateIndex; // Index of the oldest state variable in the array of state variables. FLOAT32* state; // State variable array. } ModuleDelayMixerSmoothedClass;

Variables

Properties

Name

Type

Usage

isHidden

Default value

Range

Units

maxDelayTime

float

const

0

10

0:10

msec

smoothingTimeDelay

float

parameter

0

10

0:1000

msec

smoothingTimeGain

float

parameter

0

10

0:1000

msec

smoothingCoeff

float

derived

1

0.002081

Unrestricted

 

smoothingCoeffGain

float

derived

1

0.002081

Unrestricted

 

stateHeap

int

const

1

561

Unrestricted

 

maxDelay

int

const

1

480

Unrestricted

 

prevDelay

int*

state

1

[1 x 1]

Unrestricted

samples

currentDelay

int*

state

1

[1 x 1]

Unrestricted

samples

prevGain

float*

state

1

[1 x 1]

Unrestricted

samples

currentGain

float*

state

1

[1 x 1]

Unrestricted

samples

oldGain

float*

state

1

[1 x 1]

Unrestricted

 

newGain

float*

state

1

[1 x 1]

Unrestricted

 

fadingDone

int*

state

1

[1 x 1]

0:1

 

stateIndex

int*

state

1

[1 x 1]

Unrestricted

 

state

float*

state

1

[1 x 515]

Unrestricted

 

Pins

Input Pins

Name: in

Description: audio input

Data type: float

Channel range: Unrestricted

Block size range: Unrestricted

Sample rate range: Unrestricted

Complex support: Real

 

Name: cntrl

Description: Control pin for MxN gain and delays

Data type: float

Channel range: Unrestricted

Block size range: Unrestricted

Sample rate range: Unrestricted

Complex support: Real

Output Pins

Name: out

Description: Audio output

Data type: float

Scratch Pins

Channel count: 1

Block size: 64

Sample rate: 48000

 

Channel count: 1

Block size: 32

Sample rate: 48000

MATLAB Usage

File Name: delay_mixer_smoothed_module.m

M=delay_mixer_smoothed_module(NAME, NUMCHANNELS, MAXDELAY, MEMHEAP) Creates a multi-channel time delay in which the delay times are specified in milliseconds. The module has a multichannel input pin and an multichannel output pin. Each output channel is a mix of all the input channels with a dedicated delay and mix level for each input channel. The module applies smooth transition between delay time changes as well as mixer levels. Arguments: NAME - name of the module. NUMCHANNELS - number of output channels for the module. MAXDELAY - maximum delay, in milliseconds. MEMHEAP - specifies the memory heap to use to allocate the main state buffer. This is a string and follows the memory allocation enumeration in Framework.h. Allowable values are: 'AWE_HEAP_FAST' - always use internal DM memory. 'AWE_HEAP_FASTB' - always use internal PM memory. 'AWE_HEAP_SLOW' - always use external memory. 'AWE_HEAP_FAST2SLOW' - use internal memory. If this fails then use external memory (the default). 'AWE_HEAP_FASTB2SLOW' - use internal memory. If this fails then use external memory.