audio-frequency-to-index

Convert a Hz frequency to an index for WebAudio frequency analysis. Also see audio-index-to-frequency.

The value is clamped between [ 0 .. frequencyBinCount ]. The frequencyBinCount is the same as ananlyserNode.fftSize / 2.

const freq2index = require('audio-frequency-to-index')
const sampleRate = audioContext.sampleRate // 44100
const length = analyserNode.frequencyBinCount // 1024
 
const index = freq2index(400, sampleRate, length)
//=> 19

Usage

index = frequencyToIndex(frequency, sampleRate, frequencyBinCount)

Converts frequency (in Hz) to an index integer using the audioContext.sampleRate and analyserNode.frequencyBinCount from the Web Audio API.

License

MIT, see LICENSE.md for details.