/ Examples / Filters / BiQuad

BiQuad

A digital biquadratic filter is a meat-and-potatoes filter that allows to to select one resonant peak and one notch. Each is accompanied by a Radius that controls the inverse-width of the feature, analogous to the filter Q, or quality.

PoleFreq sets the resonant frequency expressed in Hz.

PoleRadius controls the quality of the resonance. In this case the radius must always be less than 1 to prevent feedback. It's common to have values in the range .9 - .9995.

ZeroFreq sets the notch frequency expressed in Hz. To achieve pure resonance you can set this value to 0.

ZeroRadius controls the quality of the notch.

Normalize when set, creates zeros automatically to ensure that the filter gain is constant. When this is checked the zero settings are disregarded.

Equal Gain Zeros when set, the values for ZeroRadius and ZeroFreq are disregarded and the result is no zeros.

Gain multiplies input signal before filtering it.

The example

In this example we feed BiQuad with a periodic Impulse generated by the Trigger node (a CCGenerator). We also generate a sweeping value for PoleFreq.