Пропуски при записи звука при помощи waveInOpen

Public Sub MonitorAudio()
Dim WHrec As WAVEHDR
Dim WFrec As WAVEFORMATEX
Dim Rv&
Dim x As Long
With WFrec
    .wFormatTag = WAVE_FORMAT_PCM
    .nChannels = 2
    .wBitsPerSample = 16
    .nSamplesPerSec = 8000
    .nBlockAlign = (.nChannels * .wBitsPerSample) / 8
    .nAvgBytesPerSec = 32000
    .cbSize = BufLEN * 32000
End With
Rv = waveInOpen(hWaveIn, RecDevice, WFrec, AddressOf waveInProc, 0, CALLBACK_FUNCTION)
If Rv <> 0 Then
    Exit Sub
End If
DoEvents

waveInStart hWaveIn

With WHrec
    .lpData = VarPtr(WaveData(0))
    .dwBufferLength = BufLEN * 32000
    .dwFlags = 0
End With

waveInPrepareHeader hWaveIn, WHrec, Len(WHrec)
bBufferFull = False
waveInAddBuffer hWaveIn, WHrec, Len(WHrec)

Do
    Do
        DoEvents
    Loop Until bBufferFull Or hWaveIn = 0
    waveInPrepareHeader hWaveIn, WHrec, Len(WHrec)
    waveInAddBuffer hWaveIn, WHrec, Len(WHrec)
Loop Until hWaveIn = 0
End Sub