I was a psychology major . . . and my professors were quite convinced that only one study existed that showed listening to classical music improved test scores over rock music or no music. Other studies were unable to replicate the results, especially when the subjects were taking different kinds of tests. In fact, studies involving test-taking have consistently shown that having no kind of distraction is better than having any distraction, including music. So, no, there is no reason to believe that specific sounds or music have anything to do with synchronizing with your brain waves or anything of the kind -- that's a scam.
As far as the "brainwaves" stuff -- as a neuroscience geek myself, it sounds like utter bull****. Yes, brains have waves, but the notion that we know exactly what Einstein's or Da Vinci's brainwaves looked like when they came up with great ideas is so crazy that I actually laughed when reading the website. We do not know enough about the brain . . . using "we" loosely to mean people in the medical and neuroscience fields . . . to use sounds to make people smarter or brains more "efficient." Trust me, if we knew that, it would be in textbooks all over the place already (new editions come out every year) and universities would be studying it and perfecting methods like crazy. Psychology and neuroscience professors would be scrambling to compete for grants to do this stuff. That work hasn't been done, and this is a scam. This scam is designed for people who have no psychology or neuroscience background and therefore have a much-exaggerated opinion of what scientists know about the brain . . . the same kind of people who believe that we're very near making various kinds of mind-control chips (which, fyi, we aren't). Specific sequencing of brainwaves to maximize performance for different tasks is WAY beyond our current knowledge level.
I would look this up and prove it to you, but I don't have academic library access at the moment (out of undergrad, not in med school yet). I strongly suggest that people who do have access look this up on "psychinfo", which is the psychology academic database. I'm curious to double-check what I remember as well, and it's frusterating that I can't.