Women’s Health discusses how white noise machines can help you get a proper night’s sleep.

“White noise is basically a constant noise that covers all hearable frequencies,” says Rajkumar (Raj) Dasgupta, M.D., assistant professor of clinical medicine at Keck School of Medicine at the University of Southern California. “We [often] use the terminology of ‘white noise’ wrong. Not everything that is labeled ‘white noise’ is truly white noise. People love the sound of rainfall in the background and find it soothing and peaceful—but that’s not meeting the definition of white noise.”

Josna Adusumilli, M.D., a neurologist and sleep disorders physician at Massachusetts General Hospital, breaks it down further by explaining that white noise is random noise that’s generated with snips from all frequencies (hence why that babbling brook or crackling fire doesn’t count).