feedback)

# 功能描述

创建一个IIRFilterNode

# 参数

# Array.<number> feedforward

一个浮点值数组，指定IIR滤波器传递函数的前馈(分子)系数。

# Array.<number> feedback

一个浮点值数组，指定IIR滤波器传递函数的反馈(分母)系数。

# 返回值

# IIRFilterNode

# 示例代码


let lowPassCoefs = [
  {
    frequency: 200,
    feedforward: [0.00020298, 0.0004059599, 0.00020298],
    feedback: [1.0126964558, -1.9991880801, 0.9873035442]
  },
  {
    frequency: 500,
    feedforward: [0.0012681742, 0.0025363483, 0.0012681742],
    feedback: [1.0317185917, -1.9949273033, 0.9682814083]
  },
  {
    frequency: 1000,
    feedforward: [0.0050662636, 0.0101325272, 0.0050662636],
    feedback: [1.0632762845, -1.9797349456, 0.9367237155]
  },
  {
    frequency: 5000,
    feedforward: [0.1215955842, 0.2431911684, 0.1215955842],
    feedback: [1.2912769759, -1.5136176632, 0.7087230241]
  }
]

const feedForward = lowPassCoefs[filterNumber].feedforward
const feedBack = lowPassCoefs[filterNumber].feedback
const iirFilter = audioContext.createIIRFilter(feedForward, feedBack)