White noise (and pink and brown): The science behind the sounds What’s your favorite bedtime jam? Do you doze off to jazz, a babbling brook, a crackling fire or a whirling fan of white noise? Or maybe you’re a sound aficionado, and have replaced your white noise machine with one that provides the more fashionable pink or brown noise? Whatever your pleasure, know this: While continuously listening to low decibel calming sounds at night doesn’t appear to be harmful, there also isn’t much science behind how, why — or even if — sound machines help sleep. “So many people are using it that the public health consequences of this are potentially ‘ginormous,’ yet right now we have little to no research on this,” said Dr. Mathias Basner, a professor in the division of sleep and chronobiology at the University of Pennsylvania School of Medicine, who published a systematic review of research on noise as a sleep aid.