Как выключить звук?

uses 
  MMSystem; 
 
function GetMasterMute( 
  Mixer: hMixerObj; 
  var Control: TMixerControl): MMResult; 
  // Returns True on success 
var 
  Line: TMixerLine; 
  Controls: TMixerLineControls; 
begin 
  ZeroMemory(@Line, SizeOf(Line)); 
  Line.cbStruct := SizeOf(Line); 
  Line.dwComponentType := MIXERLINE_COMPONENTTYPE_DST_SPEAKERS; 
  Result := mixerGetLineInfo(Mixer, @Line, 
    MIXER_GETLINEINFOF_COMPONENTTYPE); 
  if Result = MMSYSERR_NOERROR then 
  begin 
    ZeroMemory(@Controls, SizeOf(Controls)); 
    Controls.cbStruct := SizeOf(Controls); 
    Controls.dwLineID := Line.dwLineID; 
    Controls.cControls := 1; 
    Controls.dwControlType := MIXERCONTROL_CONTROLTYPE_MUTE; 
    Controls.cbmxctrl := SizeOf(Control); 
    Controls.pamxctrl := @Control; 
    Result := mixerGetLineControls(Mixer, @Controls, 
      MIXER_GETLINECONTROLSF_ONEBYTYPE); 
  end; 
end; 
 
procedure SetMasterMuteValue( 
  Mixer: hMixerObj; 
  Value: Boolean); 
var 
  MasterMute: TMixerControl; 
  Details: TMixerControlDetails; 
  BoolDetails: TMixerControlDetailsBoolean; 
  Code: MMResult; 
begin 
  Code := GetMasterMute(0, MasterMute); 
  if Code = MMSYSERR_NOERROR then 
  begin 
    with Details do 
    begin 
      cbStruct := SizeOf(Details); 
      dwControlID := MasterMute.dwControlID; 
      cChannels := 1; 
      cMultipleItems := 0; 
      cbDetails := SizeOf(BoolDetails); 
      paDetails := @BoolDetails; 
    end; 
    LongBool(BoolDetails.fValue) := Value; 
    Code := mixerSetControlDetails(0, @Details, 
MIXER_SETCONTROLDETAILSF_VALUE); 
  end; 
  if Code <> MMSYSERR_NOERROR then 
    raise Exception.CreateFmt('SetMasterMuteValue failure, '+ 
      'multimedia system error #%d', [Code]); 
end; 
 
// Example: 
 
procedure TForm1.Button1Click(Sender: TObject); 
begin 
  SetMasterMuteValue(0, CheckBox1.Checked); // Mixer device #0 mute on/off 
end;

Взято с сайта https://www.swissdelphicenter.ch/en/tipsindex.php