Your brain has five different types of waves. Generally speaking, low-frequency waves are linked to “delta” and “theta” states which can boost relaxation and improve sleep. Higher frequencies reportedly boost your brain waves into a “gamma” state which may make you more alert, focused, or better able to recall memories.
Mid-range frequencies have been linked to attention. Your brain moves into an “alpha” state when your focus turns inward (as in meditation) and a “beta” state when your attention is tuned to the world around you.
“There’s lots of evidence that brain waves correlate with these stages,” says Smith, and makers of binaural beats believe they can help people navigate between them all. (from this Healthline article)
Are these claims true? I don't know. All I do know is that I find it helpful to listen to songs like the one below when I'm writing and working. And also that the words "Super Intelligence" in the title make me feel slightly embarrassed.