(8.D.2.3) DelayNChan
- Catherine Spain
Overview
Module with different time delay for each channel specified in samples
Discussion
This time delay module has multiple input and multiple output channels. The delay in samples of each output channel can be independently set by the currentDelay array. The initial number of channels is specified at construction time and this also equals the length of the currentDelay array. Actual size of the currentDelay is updated in the prebuild function. Delays are specified in samples 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 delay in samples per channel is specified by the currentDelay array. Delays can be adjusted at run-time. However, the module is not smoothly updating and you may get audible clicks when adjusting the currentDelay at run-time.
Type Definition
typedef struct _ModuleDelayNChan
{
ModuleInstanceDescriptor instance; // Common Audio Weaver module instance structure
INT32 maxDelay; // Maximum delay, in samples.
INT32 stateHeap; // Heap in which to allocate memory.
INT32* currentDelay; // Current delay per channel, in samples.
INT32* stateIndex; // Index of the oldest state variable in the array of state variables.
FLOAT32* state; // State variable array.
} ModuleDelayNChanClass;Variables
Properties
Name | Type | Usage | isHidden | Default value | Range | Units |
maxDelay | int | const | 1 | 100 | Unrestricted | samples |
stateHeap | int | const | 1 | 561 | Unrestricted | Â |
currentDelay | int* | parameter | 0 | [1 x 1] | 0:100 | samples |
stateIndex | int* | state | 1 | [1 x 1] | Unrestricted | Â |
state | float* | state | 1 | [1 x 103] | Unrestricted | Â |
Pins
Input Pins
Name: in
Description: audio input
Data type: {float, int, fract32}
Channel range: Unrestricted
Block size range: Unrestricted
Sample rate range: Unrestricted
Complex support: Real
Output Pins
Name: out
Description: audio output
Data type: {float, int, fract32}
MATLAB Usage
File Name: delaynchan_module.m
M=delaynchan_module(NAME, NUMCHANNELS, MAXDELAY, MEMHEAP)
Creates a multi-channel time delay. The module has a multichannel input pin
and an multichannel output pin. Each output channel is a delayed
version of the corresponding input channel with different delay times
per channel.
Arguments:
NAME - name of the module.
NUMCHANNELS - number of channels for the module.
MAXDELAY - maximum delay, in samples.
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.Â