A video captured by the seaside shows the deep blue ocean, with turbulent waves crashing against the coastal rocks. This footage was filmed by Mr. Song, in Caofeidian, Tangshan, Hebei, at 22:00 ...

Maybe you even use pink noise, like the gentle crash of ocean waves against the shore, to get to sleep. But there's another frequency to try: brown noise, also called Brownian noise or red noise ...