NOTE: This software is unsupported and is no longer being updated or maintained. It likely will not work on newer versions of macOS.

NotNotchFilter is a performance-oriented filter designed to replace the mid-EQ found in a standard 3-band DJ mixer. The key advantage of this filter is that it cleanly cuts out single voices or instruments in a track, whereas a standard 3-band filter dampens them. This is because NotNotchFilter, as the name suggests, is not actually a notch filter. Rather, it is a combination of a hipass and lopass filter which work on opposite sides of the target frequency.

NotNotchFilter User Interface


For optimal use, use NotNotchFilter with two knobs, one to control the base frequency and the other to control the valley size. The “valley size” measures how far apart the hipass and lopass filter are, so at 0 Hz the filter will be 100% dry, and at 20 kHz it will cut almost all sound. In the above screenshot, the filter will produce a gap of approximately 351 Hz centered around the base frequency of 400 Hz.

If you don’t have two spare knobs on your controller of choice, then assign a single knob to the valley size parameter, and then tweak the base frequency to something in the mid-hi range. You’ll probably need to experiment a bit to find a good frequency which suits your style of play, but having a spare knob to control the base frequency is preferred, as this allows one to adjust it on the fly to filter out a given instrument in the track.


NotNotchFilter is licensed under the GPL2 License, which can be found in the LICENSE.txt file included in the source code.


Version 2.0.0:

  • Plugin now has a GUI editor!
  • Fix click when filter activated
  • Minor performance improvements
  • Add 64-bit builds on all platforms
  • Constructed a custom frequency curve for valley size parameter for optimal real-world usage scenarios
  • Updated documentation (README)
  • License changed to GPL2

Version 1.0.1:

  • Parameters saved/restored correctly

Version 1.0.0:

  • First stable public release
  • Add Windows build

Version 0.9.1:

  • Tweak parameter ranges to make filter more friendly for DJ’ing
  • Cut from base frequency up, not both directions

Version 0.9: (No comment)