Stereo Pre-built DirectX Example: 4-band (octave) combo effect implemented using polyphase IIR all-pass second-order up
and down samplers.
HINT: YOU CAN CHOOSE ANY WAVEWARP DRAWINGBOARD AS A DIRECTX STEREO PLUGIN -- NOT JUST THE
ONES CONTAINED IN THIS "DirectX/Stereo" CATEGORY. WAVEWARP WILL AUTOMATICALLY CONVERT ANY
DRAWINGBOARD INTO THE REQUIRED FORMAT. THE PRE-CONVERTED EXAMPLES IN THIS DIRECTORY
ARE SIMPLY TO DEMONSTRATE THE EXPLICIT FORMAT OF MONO DIRECTX DRAWINGBOARDS. SO, AFTER
YOU'VE TRIED THESE, JUST BROWSE TO ANY OTHER EXAMPLE DRAWINGBOARD IN THE ENTIRE DISTRIBUTION --
OR BETTER STILL, GO INTO WAVEWARP AND BUILD YOUR OWN!
This is a good example of multi-rate signal processing whereby extremely efficient processing can be achieved by
successively downsampling the signal such that each "band" is running at a lower sample rate. In this example, each
band is an octave lower than the previous (due to the factor of 2 downsampling). The downsamplers are implemented
using 2-channel recursive filter banks (consisting of complementary hi - lo allpass filters implemented in polyphase form).
This is the most efficient method of implementing the filter banks. Each frequency band has a separately adjustable effect,
creating an interesting multi-layered effect. Use the switch to bypass the effect to compare with the original. (However, since
these IIR filters do not exhibit linear-phase characteristics they may be unacceptable in some applications.) This DrawingBoard
clearly illustrates the powerful multi-rate functionality of WaveWarp, a key feature of the software.
