// note: DevicesNames must be created before calling this procedure 

uses mmsystem;

 procedure GetWaveOutDevices(DeviceNames: TStrings);
 var
 DNum: Integer;
 i: Integer;
 Caps: TWaveOutCapsA;
 begin
 DNum := waveOutGetNumDevs; // Number of Devices 
 for i := 0 to DNum - 1 do // Query Devicenames 
 begin
 waveOutGetDevCaps(i, @Caps, SizeOf(TWaveOutCapsA));
 DeviceNames.Add(string(Caps.szPname));
 end;
 end;


 procedure TForm1.Button1Click(Sender: TObject);
 begin
 GetWaveOutDevices(Listbox1.Items);
 end;