Низкое качество записи потока

        Private _fileStream As IO.FileStream
        Public _myRecProc As Audio.RECORDPROC ' make it global, so that the GC can not remove it
        Private _byteswritten As Integer = 0
        Private _recbuffer() As Byte ' local recording buffer
        Private _recHandle As IntPtr
 
        '=======================================================
 
    Private Sub WriteWavHeader()
        Using stream As IO.FileStream = New FileStream("test1.wav", FileMode.Create, FileAccess.Write, FileShare.None)
            Dim channelCount As Integer = 2
            Dim sampleRate As Integer = 44100
            Dim bitDepth As Integer = 16
            Dim sh As UShort = 1
            Dim sh1 As UShort = channelCount * (bitDepth / 8)
            stream.Position = 0
            stream.Write(Encoding.ASCII.GetBytes("RIFF"), 0, 4)
            stream.Write(BitConverter.GetBytes(36), 0, 4)
            stream.Write(Encoding.ASCII.GetBytes("WAVE"), 0, 4)
            stream.Write(Encoding.ASCII.GetBytes("fmt "), 0, 4)
            stream.Write(BitConverter.GetBytes(16), 0, 4)
            stream.Write(BitConverter.GetBytes(sh), 0, 2)
            stream.Write(BitConverter.GetBytes(channelCount), 0, 2)
            stream.Write(BitConverter.GetBytes(sampleRate), 0, 4)
            stream.Write(BitConverter.GetBytes(sampleRate * channelCount * (bitDepth / 8)), 0, 4)
            stream.Write(BitConverter.GetBytes(sh1), 0, 2)
            stream.Write(BitConverter.GetBytes(bitDepth), 0, 2)
            stream.Write(Encoding.ASCII.GetBytes("data"), 0, 4)
            stream.Write(BitConverter.GetBytes(0), 0, 4)
        End Using
    End Sub
 
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        If IO.File.Exists("test1.wav") Then IO.File.Delete("test1.wav")
        If Audio.BASS_RecordInit(intCurAudioDevice) Then 'здесь intCurAudioDevice=-1
            _myRecProc = New Audio.RECORDPROC(AddressOf MyRecording)
            Dim recHandle As Integer = Audio.BASS_RecordStart(44100, 2, Audio.BASSFlag.BASS_RECORD_PAUSE, _myRecProc, IntPtr.Zero)
            ' start recording
            WriteWavHeader()
            _fileStream = New FileStream("test1.wav", FileMode.Open, FileAccess.Write, FileShare.None)
            _fileStream.Position = 44
            Audio.BASS_ChannelPlay(recHandle, False)
        End If
    End Sub
 
    Private Function MyRecording(ByVal handle As Integer, ByVal buffer As IntPtr, ByVal length As Integer, ByVal user As IntPtr) As Boolean
        Dim cont As Boolean = True, buf() As Byte
        If length > 0 AndAlso buffer <> IntPtr.Zero Then
            buf = New Byte(length) {}
            Marshal.Copy(buffer, buf, 0, length)
            _fileStream.Write(buf, 0, buf.Length)
            _byteswritten += length
            If _byteswritten > 800000 Then ' stop recording
                cont = False
                _fileStream.Position = 40
                _fileStream.Write(BitConverter.GetBytes(_fileStream.Length - 44), 0, 4)
                _fileStream.Close()
                _byteswritten = 0
            End If
        End If
        Return cont
    End Function
 
 
    '=========       В модуле  Audio ========================
 
    Public Declare Function BASS_ChannelPlay Lib "bass.dll" (ByVal handle As IntPtr, ByVal restart As Boolean) As Boolean
    Public Declare Function BASS_RecordInit Lib "bass.dll" (ByVal device As Integer) As Boolean
    Public Declare Function BASS_RecordFree Lib "bass.dll" () As Boolean
    Public Declare Function BASS_RecordStart Lib "bass.dll" (ByVal freq As Integer, ByVal chans As Integer, ByVal flags As Integer, ByVal proc As RECORDPROC, ByVal user As Integer) As IntPtr
    Public Delegate Function RECORDPROC(ByVal handle As Integer, ByVal buffer As IntPtr, ByVal length As Integer, ByVal user As IntPtr) As Boolean