Topics / Bitwig Studio / Bitwig Grid / Bitwig Grid Modules / Grid Shaper Modules / Chebyshev

Chebyshev

Bitwig Platform

Chebyshev module panel in Bitwig Grid
Chebyshev in Bitwig Grid 6.0.6.

A harmonic-targeting waveshaper based on the Chebyshev identity, with continuous order and optional DC removal.

What it does

Chebyshev transforms a bounded signal with a selectable polynomial order. With a sine-like input and an integer Order, the result emphasizes the corresponding harmonic; fractional values continuously move between those ideal integer cases.

Controls and ports

Control Label Official description
amount Amount Partial to target for emphasis ('3.0' represents an octave and a fifth up, for example)
no_dc No Dc Subtracts the function's inherent DC

Practical uses

  • Feed it a sine wave and set integer Orders to build specific harmonics.
  • Modulate Order slowly for continuously changing overtone structures.
  • Enable No DC when even or fractional orders shift the signal away from zero.

Things to know

  • An Order of 3 corresponds to the third partial, an octave and a fifth above the fundamental.
  • The input is hard-clamped to -1 through +1 before evaluation.
  • The clean harmonic identity is exact for a cosine-domain input and integer order; complex audio produces intermodulation as well.
  • Removing DC subtracts the function value at input zero, not a time-averaged DC measurement.

Technical details

A high-confidence Nitro implementation candidate supports the technical summary, but the visible-module mapping remains inferred.

The exact grid/shaper/chebyshev body evaluates T_a(x) = cos(a*acos(clamp(x,-1,1))). When No DC is active it subtracts T_a(0) = cos(a*pi/2). For integer a = n, this is the Chebyshev polynomial T_n; if x = cos(theta), the output is cos(n*theta). The implementation accepts audio-rate Order and performs no dedicated antialiasing inside this body.

Nitro port Type
in InputAudioPortType
order InputAudioPortType
no_dc InputValuePortType
out OutputAudioPortType

Open questions

  • Measure aliasing and amplitude for integer and fractional orders across pitch and sample rate.
  • Verify Amount range, modulation smoothing, stereo behavior, and boundary derivatives at ±1.
  • Compare No DC with measured time-average removal for asymmetric and non-sinusoidal sources.

Version and sources

Checked against Bitwig Studio 6.0.6. This page combines Bitwig's module metadata, the existing Grid course and guides, and Nitro analysis where the mapping is strong enough to support a technical statement.

Return to Bitwig Grid Modules or the Grid Modules course lesson.

Also matches: Bitwig Chebyshev module, Bitwig Grid Chebyshev, Chebyshev Grid module