const 
  dt = 'D:\win.mid'; 
 
var 
  ID: integer; 
 
procedure SetTempo(Value: Integer); 
var 
  Flags: integer; 
  SeqParm: tagMCI_SEQ_SET_PARMS; 
begin 
  zeromemory(@SeqParm, sizeof(SeqParm)); 
  SeqParm.dwTempo := Value; 
  Flags := MCI_SEQ_SET_TEMPO; 
  mciSendCommand(ID, MCI_SET, Flags, Longint(@SeqParm)); 
end; 
 
procedure SndPlay(const Datei: string); 
var 
  op: TMCI_Open_Parms; 
begin 
  zeromemory(@op, sizeof(op)); 
  op.lpstrElementName := PChar(Datei); 
  mciSendCommand(0, MCI_OPEN, MCI_OPEN_ELEMENT, integer(@op)); 
  ID := op.wDeviceID; 
  mciSendCommand(ID, MCI_PLAY, MCI_NOTIFY, integer(@op)); 
end; 
 
// Abspielen 
 
procedure TForm1.Button14Click(Sender: TObject); 
begin 
  SndPlay(dt); 
end; 
 
// Tempo ändern 
 
procedure TForm1.Button15Click(Sender: TObject); 
begin 
  SetTempo(250); 
end; 
 
// Sound stoppen 
 
procedure TForm1.Button16Click(Sender: TObject); 
begin 
  mciSendCommand(ID, MCI_CLOSE, 0, 0); 
end;