I prefer a pink noise myself. https://mynoise.net https://mynoise.net is great for this. There are loads of sound generators for different environments, each o

I prefer a pink noise myself. https://mynoise.net https://mynoise.net is great for this. There are loads of sound generators for different environments, each of which has sliders for each frequency. I sometimes use it when I have trouble falling asleep (I pin the site to my homepage on Android Chrome).