automatic voice record in c#

class MicrophoneRec {

    private Timer timer = null;
    private Microphone mic = Microphone.Default;
    List<byte[]> byteList = new List<byte[]>();
    private string outPutFile = @"D:\TempDir\test.wav";

    public void micStart(int durationToRecordSec) {

        if (mic != null) {
            timer = new Timer();
            timer.Interval = (durationToRecordSec * 1000);
            timer.Elapsed += new ElapsedEventHandler(t_Elapsed);

            mic.BufferDuration = TimeSpan.FromMilliseconds(100);
            mic.BufferReady += new EventHandler<EventArgs>(mic_BufferReady);
            timer.Start();
            mic.Start();
        }
    }

    void mic_BufferReady(object sender, EventArgs e) {

        byte[] data = new byte[mic.GetSampleSizeInBytes(mic.BufferDuration)];
        mic.GetData(data);
        byteList.Add(data);
    }

    void t_Elapsed(object sender, ElapsedEventArgs e) {

        mic.Stop();
        timer.Stop();
        byte[] buffer = new byte[byteList.Select(x => x.Length).Sum()];
        int offset = 0;
        foreach (var buff in byteList) {
            System.Buffer.BlockCopy(buff, 0, buffer, offset, buff.Length);
            offset += buff.Length;
        }

        using (FileStream fs = new FileStream(outPutFile, FileMode.Create)) {
            WaveHeader.WriteHeader(fs, buffer.Length, 1, mic.SampleRate);
            fs.Write(buffer, 0, buffer.Length);
        }
    }
}

class WaveHeader {

    static byte[] RIFF_HEADER =  new byte[] { 0x52, 0x49, 0x46, 0x46 };
    static byte[] FORMAT_WAVE =  new byte[] { 0x57, 0x41, 0x56, 0x45 };
    static byte[] FORMAT_TAG =   new byte[] { 0x66, 0x6d, 0x74, 0x20 };
    static byte[] AUDIO_FORMAT = new byte[] { 0x01, 0x00 };
    static byte[] SUBCHUNK_ID =  new byte[] { 0x64, 0x61, 0x74, 0x61 };
    private const int BYTES_PER_SAMPLE = 2;

    public static void WriteHeader(System.IO.Stream targetStream,
         int byteStreamSize, int channelCount, int sampleRate) {

        int byteRate = sampleRate * channelCount * BYTES_PER_SAMPLE;
        int blockAlign = channelCount * BYTES_PER_SAMPLE;

        targetStream.Write(RIFF_HEADER, 0, RIFF_HEADER.Length);
        targetStream.Write(PackageInt(byteStreamSize + 42, 4), 0, 4);

        targetStream.Write(FORMAT_WAVE, 0, FORMAT_WAVE.Length);
        targetStream.Write(FORMAT_TAG, 0, FORMAT_TAG.Length);
        targetStream.Write(PackageInt(16, 4), 0, 4);//Subchunk1Size

        targetStream.Write(AUDIO_FORMAT, 0, AUDIO_FORMAT.Length);//AudioFormat
        targetStream.Write(PackageInt(channelCount, 2), 0, 2);
        targetStream.Write(PackageInt(sampleRate, 4), 0, 4);
        targetStream.Write(PackageInt(byteRate, 4), 0, 4);
        targetStream.Write(PackageInt(blockAlign, 2), 0, 2);
        targetStream.Write(PackageInt(BYTES_PER_SAMPLE * 8), 0, 2);
        targetStream.Write(SUBCHUNK_ID, 0, SUBCHUNK_ID.Length);
        targetStream.Write(PackageInt(byteStreamSize, 4), 0, 4);
    }

    static byte[] PackageInt(int source, int length = 2) {
        if ((length != 2) && (length != 4))
            throw new ArgumentException("length must be either 2 or 4", "length");
        var retVal = new byte[length];
        retVal[0] = (byte)(source & 0xFF);
        retVal[1] = (byte)((source >> 8) & 0xFF);
        if (length == 4) {
            retVal[2] = (byte)((source >> 0x10) & 0xFF);
            retVal[3] = (byte)((source >> 0x18) & 0xFF);
        }
        return retVal;
    }
}