HOW to select "MICROPHONE" as recording input device

uses
  MMSystem;

// Setzt die Lautstärke für das Mikrofon
// Set the volume for the microphone

procedure SetMicrophoneAsDefaultDevice;
var                          {0..65535}
  hMix: HMIXER;
  mxl: TMixerLine;
  intRet: Integer;
  nMixerDevs: Integer;
begin
  // Check if Mixer is available
  nMixerDevs := mixerGetNumDevs();
  if (nMixerDevs < 1) then
  begin
    Exit;
  end;

  // open the mixer
  intRet := mixerOpen(@hMix, 0, 0, 0, 0);
  if intRet = MMSYSERR_NOERROR then
  begin
    mxl.dwComponentType := MIXERLINE_COMPONENTTYPE_SRC_MICROPHONE;
   
  //Here what ever do you want to do...
   
  end;
end;