[nwn]

Код:

procedure SetPort(address, Value:Word);
var
  bValue: byte;
begin
  bValue := trunc(Value and 255);
  asm
    mov dx, address
    mov al, bValue
    out dx, al
  end;
end;

function GetPort(address:word):word;
var
  bValue: byte;
begin
  asm
    mov dx, address
    in al, dx
    mov bValue, al
  end;
  GetPort := bValue;
end;

procedure Sound(Freq : Word);
var
  B : Byte;
begin
  if Freq > 18 then
  begin
    Freq := Word(1193181 div LongInt(Freq));
    B := Byte(GetPort($61));
    if (B and 3) = 0 then
    begin
      SetPort($61, Word(B or 3));
      SetPort($43, $B6);
    end;
    SetPort($42, Freq);
    SetPort($42, Freq shr 8);
  end;
end;

procedure NoSound;
var
  Value: Word;
begin
  Value := GetPort($61) and $FC;
  SetPort($61, Value);
end;

procedure Beep(Tone, Duration: Word);
begin
  if SysUtils.Win32Platform = VER_PLATFORM_WIN32_NT then
    Windows.Beep(Tone, Duration)
  else
  begin
    Sound(Tone);
    Windows.Sleep(Duration);
    NoSound;
  end;
end;

И потом, например, при VCL:

Код:

procedure TForm1.Button1Click(Sender: TObject);
begin
Beep(100,100);
end;

PS. Не забудь функции(и процедуры) объявить