I agree with you, it doesn't sound as real as I wished it to be. Cat Purr was a request of many early myNoise users. At beginning, I kept explaining all the reasons why the myNoise sound player was not designed for playing a cat purr (it was initially designed to play random-phase and flat spectrum noises such as white noise and rain) and why I wouldn't implement a cat purr. Then, I gave up and programmed it, just to stop people asking :D It is not the myNoise sound I am the most proud of, but it seems that people like it (or the concept).