根据频率创建音频文件

此函数将使用浮点值填充缓冲区，该浮点值表示给定频率下原始音频曲线的高度

var pop_audio_buffer_custom = function (number_of_samples, given_freq, samples_per_second) {

    var number_of_samples = Math.round(number_of_samples);

    var audio_obj = {};
    
    var source_buffer = new Float32Array(number_of_samples);

    audio_obj.buffer = source_buffer;

    var incr_theta = (2.0 * Math.PI * given_freq) / samples_per_second;
    var theta = 0.0;

    for (var curr_sample = 0; curr_sample < number_of_samples; curr_sample++) {

        audio_obj.buffer[curr_sample] = Math.sin(theta);

        console.log(audio_obj.buffer[curr_sample] , "theta ", theta);

        theta += incr_theta;
    }
    
    return audio_obj;

};       //      pop_audio_buffer_custom

var number_of_samples = 10000; // long enough to be audible
var given_freq = 300;
var samples_per_second = 44100;  // CD quality sample rate
var wav_output_filename = "/tmp/wav_output_filename.wav"

var synthesized_obj = {};

synthesized_obj.buffer = pop_audio_buffer_custom(number_of_samples, given_freq, samples_per_second);

数字音频的世界是不平凡的... ...一旦有了音频缓冲区，下一步就是将浮点表示形式转换为可以存储的字节（通常是16位整数，取决于您选择的位深）。然后将16位整数缓冲区作为WAV文件写出

音频是一种有时被称为时间序列的波...当您将拳头砸在桌子上时，桌子上下摆动，从而将微小的空气分子与该摆动一致地推动...这种空气的摆动在整个房间中传播并到达麦克风振膜或您的鼓膜，然后随着该波而摆动……如果您将铅笔粘在振膜上，使其随振膜一起摇摆，然后沿着铅笔的笔尖慢慢滑动一条纸条，看到一条曲线写在纸条上...这是音频曲线...音频样本只是该曲线在瞬间的高度...如果您反复记下该曲线的高度值X次以恒定的速度每秒，您将获得原始音频的数据点列表（这是上面的函数创建的）...所以给定的音频样本只是给定时刻的音频曲线高度的值...由于计算机不是连续的而是分散的，它们无法处理整个铅笔绘制的曲线，因此仅关心此瞬时测量的曲线高度列表值...这些是音频样本

高于32位浮点缓冲区的数据可以输入以下函数以返回16位整数缓冲区

var convert_32_bit_float_into_signed_16_bit_int_lossy = function(input_32_bit_buffer) {

    // this method is LOSSY - intended as preliminary step when saving audio into WAV format files
    //                        output is a byte array where the 16 bit output format 
    //                        is spread across two bytes in little endian ordering

    var size_source_buffer = input_32_bit_buffer.length;

    var buffer_byte_array = new Int16Array(size_source_buffer * 2); // Int8Array 8-bit twos complement signed integer

    var value_16_bit_signed_int;
    var index_byte = 0;

    console.log("size_source_buffer", size_source_buffer);


    for (var index = 0; index < size_source_buffer; index++) {

        value_16_bit_signed_int = ~~((0 < input_32_bit_buffer[index]) ? input_32_bit_buffer[index] * 0x7FFF : 
                                                                        input_32_bit_buffer[index] * 0x8000);

        buffer_byte_array[index_byte] = value_16_bit_signed_int & 0xFF; // bitwise AND operation to pluck out only the least significant byte

        var byte_two_of_two = (value_16_bit_signed_int >> 8); //  bit shift down to access the most significant byte

        buffer_byte_array[index_byte + 1] = byte_two_of_two;

        index_byte += 2;
    };

    // ---

    return buffer_byte_array;
};

下一步是将16位int缓冲区以上的内容持久保存到wav文件中……我建议您为此使用许多nodejs库之一（或者最好将其自己编写为仅两页代码；-)）