带通滤波器，哪个频率和Q值代表频率范围？

Question

我想使用网络音频带通滤波器来强调从 300Hz 到 3kHz 的频率。

然而 bandpass filter in the Web Audio API has only one frequency value (representing the center) and one Q 值（代表八度？）。

如何正确设置它们以代表我的 to 和 from 频率范围？

Answer 1

var from = 300;
var to = 30000;
var geometricMean = Math.sqrt(from * to);

var filter = audioContext.createBiquadFilter();
filter.type = 'bandpass';
filter.frequency.value = geometricMean;
filter.Q.value = geometricMean / (to - from);

频率似乎是 geometric mean of the from and to value. With this value as center frequency I am now able to calculate the Q 值。