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Rare Waves
Grendel Formant Filter - 12HP

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Item: N13-2250

Availability: In stock

Grendel Formant Filter - 12HP

Introducing the Grendel Formant Filter in Eurorack modular format.

Four analog bandpass filters in parallel, plus a control voltage processor to articulate vowel-like tones from your audio input.

The Grendel Formant Filter has three control voltage (CV) inputs: Size, Articulator X, and Articulator Y. These are optimized for 5 volt analog control signals,
but can accept up to +/-10 volts.

The Size parameter moves all four BPFs in parallel. This affects the overall size of the filter’s ‘mouth’, from oversized to midget.

Articulators X and Y work together to select vowel tones from a two-dimensional map related to the IPA Vowel Chart. For optimum control, these inputs can be connected to an analog joystick controller or two channels of a MIDI-CV converter. The ideal voltage range for controlling Articulators X and Y is +/- 2.5 volts, or 0..+5 volts.

Suggested signal sources for the CV inputs are LFO, envelope generator, MIDI-CV converter, analog joystick controller, etc.


  • Size Control
  • Size CV Input
  • Articulator X Control
  • Articulator X CV Input
  • Articulator Y Control
  • Articulator Y CV Input
  • Gain Control
  • Audio In/Out

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  • Eurorack Format
  • 12HP Width
  • 30mm Depth
  • Reverse Polarity Protection
  • +12v: 65mA Current Draw
  • -12v: 65mA Current Draw

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