Most of the sound loops are very harsh-sounding and give me a headache instead of helping me sleep.The mode I got it for, white noise, is one of the worst. Other samples seem to be as long as 20 seconds, the white noise sample is about 2 seconds long. The brain is very good about picking out patterns - especially when it is such a short sample. Imagine hearing a pattern looping over and over all night long... not fun. It's sad, too, because it would be so easy to design something to generate true white noise. Maybe add some options to adjust the frequency range and you're done.My wife got one of the noise generators that is a fan with some adjustments to control the air flow. This works much better, but could be made into an electronic device that would cost less than 1/4 what that thing costs.