about the bat filter:
the bat filters card is a collection of 8 voltage controlled digital filters (vcdf).
compared to their analog cousins, digital filters are precise and deep. they can remove or pass selected harmonics smoothly or aggressively depending on how they're configured. the result is special character that brings a whole new sonic dimension to the analog modular synthesizer.
the bat filter algorithms are based on the chebyshev filter topology. they're pumping at low frequencies, smooth and pleasant at mid range, and aggressive up top as the audio frequency gets closer to the dsp sampling rate. one of the biggest advantages of digital filter design is the ability to cascade filters with no gain loss or added circuit noise like with analog filters. this results in filters with up to 8poles, a slope of 48db!! that's equivalent to having four 12db analog filters in series, yet maintaining a clean, strong signal at the output.
the bat filter contains the following algorithms:
program - a dual stereo 8pole low pass filter. each filter has a separate cutoff on the z-dsp with common resonance.
program - dual 8pole band pass
program - 4pole high pass / low pass in series
program - 8pole high pass / band pass in series
program - 8pole triple band reject (notch filters)
program - 8pole high pass / band reject in series
program - stereo resonator, a unique dynamically varied structure of filters creating a powerful resonator with stereo spread control, ideal for pads and drones
program - stereo 8pole high pass filter with stereo spread control