The IIRFilterNode() constructor of the Web Audio API creates a new IIRFilterNode object which an AudioNode processor which implements a general infinite impulse response filter.


var iIRFilterNode = new IIRFilterNode(context, options)



A reference to an AudioContext.


Options are as follows:

  • feedforward: A sequence of feedforward coefficients.
  • feedback: A sequence of feedback coefficients.
  • channelCount: Represents an integer used to determine how many channels are used when up-mixing and down-mixing connections to any inputs to the node. (See AudioNode.channelCount for more information.) Its usage and precise definition depend on the value of channelCountMode.
  • channelCountMode: Represents an enumerated value describing the way channels must be matched between the node's inputs and outputs. (See AudioNode.channelCountMode for more information including default values.)
  • channelInterpretation: Represents an enumerated value describing the meaning of the channels. This interpretation will define how audio up-mixing and down-mixing will happen. The possible values are "speakers" or "discrete". (See AudioNode.channelCountMode for more information including default values.)

Unlike other nodes in the Web Audio API, the options passed into the IIR filter upon creation are not optional. The filter needs these values to work and with the vast range of filters available, there is no default.

Return value

A new IIRFilterNode object instance.


let feedForward = [0.00020298, 0.0004059599, 0.00020298];
let feedBackward = [1.0126964558, -1.9991880801, 0.9873035442];

const AudioContext = window.AudioContext || window.webkitAudioContext;
const audioCtx = new AudioContext();

const iirFilter = new IIRFilterNode(audioCtx, { feedforward: feedForward, feedback: feedBackward });


Web Audio API
# dom-iirfilternode-constructor-iirfilternode

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