Variable Slope VCF

A classic highly resonant 2-pole filter based around a classic 4U Modular Filter design with HP, LP, and BP outputs.

“The VARIABLE SLOPE VCF (VCFS) offers unique control of sound quality offered by no other synthesizer manufacturer. All VCF's offer voltage control of the cut--off frequency, that. is, control of which frequencies the filter lets pass . The VCFS allows the amount of
filtering to be dynamically controlled as well, from barely perceptible filtering to highly resonant, sharp cut-offs . With the variable slope control in the center position, the VCFS acts as a typical flat-response VCF, with high, low, and band--pass outputs
available simultaneously . The slope of the cutoff is 12 db/octave . As the control is moved toward the maximum position, the resonance of the filter increases, so that the cutoff becomes sharper . Although the VCFS will not ring like the VCFQ, it will resonate enough at the
maximum setting to pick out harmonics from a complex; signal input . As the control is moved to the minimum position, the cut-off slope will decrease to 6 db/octave. This type of change of filter, slope has been found to be an effective synthesis technique corresponding well with
some of the transformations in acoustic instrument sounds . There are two signal inputs to the VCFS which can be mixed and manually crossfaded from the associated knob ..”

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