I originally made this plug-in for a specific job, but have now adapted it to be a more general resonant filter effect.
It is designed with sound synthesis in mind, particularly as a tool in producing “analogue” style synthesizer sounds, though other uses may be found.
It could be adapted to produce sweeping resonant filters, but in this version the filter frequency is set with a slider control.
Central to the code is the Nyquist function (reson sound center bandwidth n)
The plug-in requires Audacity 1.3.x and will work with mono or stereo tracks. As resonant filters can produce very high peaks, the output is normalised to full scale (+/- 1.0)
reson.ny (857 Bytes)
and a very short synthesized sound in which the filter was used: