BEAP 5d SVF Filter
A BEAP implementation of the Synthcore 2.1 5d SVF filter, which is completely implemented in Cycling74 gen~ codebox. A demo patch, illustrated, shows some possibilities.
The filter can be continuously modulated in five dimensions:
- Cutoff. The filter is 3x oversampled, providing consistent performance up to the C8 octave at standard audio rates.
- Resonance. The resonance can increase until there is only self oscillation. The resonance curve is logarithmically shaped to provide finer control at higher resonance settings.
- Drive. The filter implements table-based gain compensation, with 60,000 entries, providing up to unity gain at all dimensional settings, although of course it may eliminate the input signal entirely at some settings, depending on the source characteristics. At lower drive settings, the filter resonance dominates the output without distortion. As drive increases, the resonance usually diminishes compared to the source and filtered signal, due to the gain compensation. As drive increases to the midpoint, the filter itself saturates. At higher drive settings, the output oversaturates in a parabolic waveshaper, also affecting any source signal in the mix, until it fully clips.
- Poles. At the lowest setting, the source signal bypasses the filter, only modified by any drive oversaturation. At lower pole settings, the source signal mixes with a 2-pole filter. At midpoint, there is only two-pole filtering. At higher pole settings, a 4-pole mixes with the 2-pole. At maximum, there is only a 4-pole filter.
- Type. The type can also be smoothly changed between low-pass, band-pass, and high-pass filter types.
Internally, the filter uses zero-crossover mixing, so all dimensions can be modulated at audio rates without clicks or distortion.
Display. The filter frequency response (yellow) displays over the input frequency analysis (red).
The preview image is fuzzy, but the video is sharp. (The clicks are mouse clicks).
Using the Module
Make sure the.wav files, which are included in the zipfile with the patches, are in the same folder. The CV inputs are all in the standard -5~+5 CV range.