(8.D.2.2) DelayNTap
- Catherine Spain
Overview
Time delay with multiple output taps
Discussion
This time delay has a single mono input and multiple output channels. The delay of each output channel can be independently set by the currentDelay array. The number of output channels (NUMTAPS) is specified at construction time and this also equals the length of the currentDelay array. 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+blockSize samples. The delay time 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 _ModuleDelayNTap
{
ModuleInstanceDescriptor instance; // Common Audio Weaver module instance structure
INT32 maxDelay; // Maximum delay, in samples.
INT32 stateIndex; // Index of the oldest state variable in the array of state variables.
INT32 stateHeap; // Heap in which to allocate memory.
INT32* currentDelay; // Current delay.
FLOAT32* state; // State variable array.
} ModuleDelayNTapClass;Variables
Properties
Name | Type | Usage | isHidden | Default value | Range | Units |
maxDelay | int | const | 0 | 100 | 1:100000 | samples |
stateIndex | int | state | 1 | 0 | Unrestricted | Â |
stateHeap | int | const | 1 | 561 | Unrestricted | Â |
currentDelay | int* | parameter | 0 | [5 x 1] | 0:1:100 | samples |
state | float* | state | 1 | [132 x 1] | Unrestricted | Â |
Pins
Input Pins
Name: in
Description: audio input
Data type: {float, int, fract32}
Channel range: 1
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: delayntap_module.m
M=delayntap_module(NAME, NUMTAPS, MAXDELAY, MEMHEAP)
Creates a multi-tap time delay. The module has a single mono input pin
and an N-channel interleaved output. Each output channel is a delayed
version of the input with different delay times per channel.
Arguments:
NAME - name of the module.
NUMTAPS - number of taps.
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