In my search for THE perfect filter (does she really exist?) I made yet another 2nd order filter. The filter is by default setup as low pass (=LP) and band pass (=BP) at the same time. With negative mixing to the original signal, one can change the filter behavior into high pass and notch. The filter is fully stereo! The tuning frequency (cutoff or center) can be changed via an audio control signal (meaning very fast or very smooth). The left and right channel can change separately. The only thing that is coupled between the channels is the resonance amount, which you will change on control rate. Several tables can be made available for different tuning frequencies and different Q(uality)-factor ranges.
This filter is using Complex (=Cmplx) number techniques to get a very stable output when one changes the cutoff frequency. One can easily make FM-like filtering effects. Listen for example to the BatleOfCmplxBP.mp3 in the module table.
Usage of the filter can be anything from a synth patch to a dedicated EQ for a DJ-mixer (low-cut / high-cut /...).
-- ChristiaanGelauff - 23 Feb 2007 Back one page
A screen dump for CmplxLPBP1: