| Parameter | Purpose |
|---|
| "Wave shaping function" selection buttons |
Selects the wave-shaping profile from a choice of 5 built-in shapes or from an
external ASCII file (for total flexibility). The chosen profile, depicted in the plot window,
defines the mapping between the input and output sample values.
The 5 built-in shapes are summarised as follows:
- "Quantization" -- mimics an A/D quantizer with arbitrary selectable resolution
- "Compression" -- reduces the dynamic range by increasing the level of low-amplitude signals
- "Expansion" -- increases the dynamic range by reducing the level of low-amplitude signals
- "Uniform noise" -- "randomizes" the signal
- "Chebyshev polynomial" -- shaping functions with the important property that they are
intrinsically band-limited i.e.
they do not introduce spurious spectral
harmonics due to overlapping etc.
|
| "Gain" slider | Scales the overall amplitude of the output signal
(after the wave-shaping has been applied). |
| "Table length" slider |
Adjusts the number of points used in the wave-shaper mapping table
(de-activated when "Load from file" is selected).
The resolution and hence the smoothness of the
mapping increases with the number of points used.
|
| "Severity" slider |
Adjusts the "severity" of the shaping profile for the
"Compression", "Expansion", and "Uniform Noise" profile options
(de-activated for all other options).
For reference, minimum severity
corresponds to a straight line with a slope of unity, thus defining
a one-to-one
mapping which has no effect on the audio.
|
| "Quantization steps" slider |
Sets the quantizer resolution
for the "Quantization" profile (de-activated for all other options).
|
| "Chebyshev order" slider |
Sets the order of the
"Chebyshev polynomial" profile (de-activated for all other options).
|
| "Load wave-shaping table from file" dialog |
Activated when
"Load from file" is selected. The wave-shaping profile is imported from
an ASCII file containing an arbitrary
user-defined shaping profile.
For convenience, the supported ASCII file format is
identical to the wavetable format used by WaveWarp's
Signal Generators
(refer to the
WaveWarp Users' Guide
for more information).
This simple file structure
enables
files to be written by hand (e.g. via a text editor).
For
MATLAB®
users, the process of creating wave-shaper profiles
is particularly straightforward.
The "wwmatlab" sub-directory of the WaveWarp root directory contains
the necessary function m-files (plus example scripts) for exporting
wavetables from MATLAB, thereby providing ready access to
MATLAB's powerful mathematical tools for creating
elaborate wave-shaping profiles.
(Refer to the
WaveWarp Users' Guide
for
a summary of all bundled m-files for working with MATLAB
in a variety of areas in addition to wave-shaper design).
|
| "Save wave-shaping table to file" dialog |
Exports the current wave-shaping profile to an ASCII file
(in wavetable format)
for future import or off-line analysis.
|
