AudioEffectFilter

Inherits: AudioEffect < Resource < RefCounted < Object

Inherited By: AudioEffectBandLimitFilter, AudioEffectBandPassFilter, AudioEffectHighPassFilter, AudioEffectHighShelfFilter, AudioEffectLowPassFilter, AudioEffectLowShelfFilter, AudioEffectNotchFilter

Base class for filters. Use effects that inherit this class instead of using it directly.

Description

A "filter" controls the gain of frequencies, using cutoff_hz as a frequency threshold. Filters can help to give room for each sound, and create interesting effects.

There are different types of filter that inherit this class:

Shelf filters: AudioEffectLowShelfFilter and AudioEffectHighShelfFilter

Band-pass and notch filters: AudioEffectBandPassFilter, AudioEffectBandLimitFilter, and AudioEffectNotchFilter

Low/high-pass filters: AudioEffectLowPassFilter and AudioEffectHighPassFilter

Tutorials

Properties

float	cutoff_hz	`2000.0`
FilterDB	db	`0`
float	gain	`1.0`
float	resonance	`0.5`

Enumerations

enum FilterDB: 🔗

FilterDB FILTER_6DB = 0

Cutting off at 6 dB per octave. One octave is twice the frequency above cutoff_hz, or half the frequency below cutoff_hz.

FilterDB FILTER_12DB = 1

Cutting off at 12 dB per octave. One octave is twice the frequency above cutoff_hz, or half the frequency below cutoff_hz.

FilterDB FILTER_18DB = 2

Cutting off at 18 dB per octave. One octave is twice the frequency above cutoff_hz, or half the frequency below cutoff_hz.

FilterDB FILTER_24DB = 3

Cutting off at 24 dB per octave. One octave is twice the frequency above cutoff_hz, or half the frequency below cutoff_hz.

Property Descriptions

float cutoff_hz = 2000.0 🔗

void set_cutoff(value: float)
float get_cutoff()

Frequency threshold for the filter, in Hz. Value can range from 1 to 20500.

FilterDB db = 0 🔗

void set_db(value: FilterDB)
FilterDB get_db()

Steepness of the cutoff curve in dB per octave (twice the frequency above cutoff_hz, or half the frequency below cutoff_hz), also known as the "order" of the filter. Higher orders have a more aggressive cutoff.

float gain = 1.0 🔗

void set_gain(value: float)
float get_gain()

Gain of the frequencies affected by the filter. This property is only available for AudioEffectLowShelfFilter and AudioEffectHighShelfFilter. Value can range from 0 to 4.

float resonance = 0.5 🔗

void set_resonance(value: float)
float get_resonance()

Gain at or directly next to the cutoff_hz frequency threshold. Value can range from 0 to 1.

Its exact behavior depends on the selected filter type:

For shelf filters, it accentuates or masks the order by increasing frequencies right next to the cutoff_hz frequency and decreasing frequencies on the opposite side.
For the band-pass and notch filters, it widens or narrows the filter at the cutoff_hz frequency threshold.
For low/high-pass filters, it increases or decreases frequencies at the cutoff_hz frequency threshold.