unit Unit1;

interface

uses
  Windows, Forms, MMSystem, Classes, Controls, StdCtrls;

type
  TForm1 = class(TForm)
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

  const
  sps	= 8000;	// samples per second
  freq1	= 1000;	 	// signal frequency (Hz)
  freq2	= 1000;	 	// signal frequency (Hz)
  freq3	= 1000;	 	// signal frequency (Hz)
  time1	= 1000;    // time of signal (ms)
  time2	= 1000;    // time of signal (ms)
  time3	= 1000;    // time of signal (ms)
  Volume1 = 32767;
  Volume2 = 32767;
  Volume3 = 32767;

type
  int16 = smallint;

var
  Form1: TForm1;
  hdr: array[0..2] of WAVEHDR;
  //second: array[0..2, 0..sps-1] of int16;	// full second
  second: array of array of int16;	// full second
implementation

{$R *.dfm}
procedure prepareSine();
var
  i, nSamples: Integer;
  angle, delta: double;
begin
  nSamples := sps * time1 div 1000;	// signal length in samples
  //
  angle := 0;
  delta := (freq1 / sps) * 2 * Pi;	// how much in one sample
  //
  for i := 0 to nSamples - 1 do begin
    //
    second[0, i] := random(Volume1*2-Volume1);//round(sin(angle) * Volume1);
    angle := angle + delta;
  end;

  nSamples := sps * time2 div 1000;	// signal length in samples
  //
  angle := 0;
  delta := (freq2 / sps) * 2 * Pi;	// how much in one sample
  //
  for i := 0 to nSamples - 1 do begin
    //
    second[1, i] := round(sin(angle) * Volume2);
    angle := angle + delta;
  end;

  nSamples := sps * time3 div 1000;	// signal length in samples
  //
  angle := 0;
  delta := (freq3 / sps) * 2 * Pi;	// how much in one sample
  //
  for i := 0 to nSamples - 1 do begin
    //
    second[2, i] := round(sin(angle) * Volume3);
    angle := angle + delta;
  end;
end;

procedure TForm1.Button1Click(Sender: TObject);
var
  i: integer;
  wout: hWaveOut;
  fmt: tWAVEFORMATEX;
begin
  SetLength(second, 3, sps);
  prepareSine();
  //
  With fmt do
  Begin
    wFormatTag := WAVE_FORMAT_PCM;
    nChannels := 1;
    nSamplesPerSec := SPS;
    wBitsPerSample := 16;
    nBlockAlign := nChannels*wBitsPerSample div 8;
    nAvgBytesPerSec := nSamplesPerSec*nBlockAlign;
    cbSize := 0;
  End;
  //
  WaveOutOpen(@wout, cardinal(-1), @fmt, 0, 0, 0);
  if (0 <> wout) then
  begin
    //
    for i := 0 to 2 do
    begin
      //
      fillChar(hdr[i], sizeof(hdr[i]), #0);
      hdr[i].lpData := @second[i];
      hdr[i].dwBufferLength := sizeof(second[i]);
      //
      waveOutPrepareHeader(wout, @hdr[i], sizeof(hdr[i]));
      WaveOutWrite(wout, @hdr[i], sizeof(hdr[i]));
    end;
    //
    //Sleep(3100);	// sleep for 3 seconds
    //
    waveOutUnprepareHeader(wout, @hdr, sizeof(TWAVEHDR));
    WaveOutClose(wout);
  end;
end;

end.

var
  hdr: WAVEHDR;

procedure TForm1.Button1Click(Sender: TObject);
var
  I, J: integer;
  wout: hWaveOut;
  fmt: tWAVEFORMATEX;
begin
  SetLength(second, 3, sps);
  prepareSine();

  with fmt do Begin
    wFormatTag := WAVE_FORMAT_PCM;
    nChannels := 1;
    nSamplesPerSec := SPS;
    wBitsPerSample := 16;
    nBlockAlign := nChannels*wBitsPerSample div 8;
    nAvgBytesPerSec := nSamplesPerSec*nBlockAlign;
    cbSize := 0;
  end;

  WaveOutOpen(@wout, cardinal(-1), @fmt, 0, 0, 0);
  if (0 <> wout) then begin
    for I := 0 to 2 do begin
      hdr.lpData := @second[i][0];
      hdr.dwBufferLength := sps;

      waveOutPrepareHeader(wout, @hdr, sizeof(hdr));
      WaveOutWrite(wout, @hdr, sizeof(hdr));
      Sleep(2100);	
    end;

    waveOutUnprepareHeader(wout, @hdr, sizeof(TWAVEHDR));
    VirtualFree(@second,0,MEM_RELEASE);
    WaveOutClose(wout);
  end;
  second := nil;
end;