<body>
<label for="duration">Duration</label>
<input
name="duration"
id="duration"
type="range"
min="0"
max="2"
value="1"
step="0.1" />
<label for="band">Band</label>
<input
name="band"
id="band"
type="range"
min="400"
max="1200"
value="1000"
step="5" />
</body>
<script>
const audioCtx = new AudioContext();
function playNoise(noiseDuration, bandHz=1000) {
const bufferSize = audioCtx.sampleRate * noiseDuration
const noiseBuffer = new AudioBuffer({
length: bufferSize,
sampleRate: audioCtx.sampleRate,
})
const data = noiseBuffer.getChannelData(0)
for (let i = 0; i < bufferSize; i++) {
data[i] = Math.random() * 2 - 1;
}
const noise = new AudioBufferSourceNode(audioCtx, {
buffer: noiseBuffer,
})
const bandpass = new BiquadFilterNode(audioCtx, {
type: "bandpass",
frequency: bandHz,
})
const gain = new GainNode(audioCtx)
gain.gain.setValueCurveAtTime([0.5, 1/10, 0], audioCtx.currentTime, noiseDuration)
noise.connect(bandpass).connect(gain).connect(audioCtx.destination)
noise.start()
}
</script>