uses
  Gorilla.Audio.FMOD,
  Gorilla.Audio.FMOD.Sound,
  Gorilla.Audio.FMOD.Channel,
  Gorilla.Audio.FMOD.System;
  
var
  FFMOD : TGorillaFMODAudioManager;
  FListenerPos : TFMOD_Vector;
  FListenerInc : Single;

procedure TForm1.FormShow(Sender: TObject);
begin
  {...}
  F3DListener := TGorillaFMOD3DListenerAttr.Create(FListenerPos); 
end;

procedure TForm1.Timer1Timer(Sender: TObject);
begin
  {...}
  // update 3d listener position : listener rotating around
  // soundsource = (0, 0, 0)
  FListenerInc := FListenerInc + 0.1;
  FListenerPos.X := Sin(FListenerInc) + 3;
  FListenerPos.Z := Cos(FListenerInc) + 3;
  F3DListener.Pos := FListenerPos;
  FFMOD.Set3DListener(F3DListener);  
end;