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let toneLengthSeconds = 1;
// Create a buffer with multiple channels.
// The signal frequency in each channel is the multiple of that in the first
// channel.
function createToneBuffer(context, frequency, duration, numberOfChannels) {
let sampleRate = context.sampleRate;
let sampleFrameLength = duration * sampleRate;
let audioBuffer =
context.createBuffer(numberOfChannels, sampleFrameLength, sampleRate);
let n = audioBuffer.length;
for (let k = 0; k < numberOfChannels; ++k) {
let data = audioBuffer.getChannelData(k);
for (let i = 0; i < n; ++i)
data[i] = Math.sin(frequency * (k + 1) * 2.0 * Math.PI * i / sampleRate);
}
return audioBuffer;
}
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