The Black DJ VCF by Erica Synths is an analogue lowpass/highpass filter in the style of Pioneer DJ mixers. In the middle position, the filter lets everything pass, turning the big knob to the left allows the low-frequency range to pass, and turning it to the right allows the higher-frequency range to pass. This mode of operation is very performance-oriented and ensures fast sound changes, as probably every clubber has heard. Thanks to a slope of 24dB the filter packs a punch; the resonance sounds musical even at full intensity. Two CV inputs add the necessary movement to the filtering when needed. The first knob is bipolar and affects the Lowpass or Highpass depending on the knob position, the second knob is unipolar and a complete range from low to high.