I'm very objective and open minded, but other than becoming relaxed, I detected no difference in my state of mind after listening to those tracks. I would become more relaxed listening to anything that was soothing or initially interesting, and so I cannot connect it to anything unique regarding the technology being promoted.

On the other hand, if I am sitting on a cliff overlooking the ocean, there is a very good chance that my brain state will truly change. The combination of the sound of the waves (and other random sounds), the sight of the waves and sunlight (and reflections), and the feel of the wind/spray, provide a full, all encompassing sensory experience, which is not redundant (meaning there are random fluctuations in what is being experienced, rather than experiencing the same exact thing over and over). I think that is what is needed to trigger a significant change in brain state. There are machines out there that try to duplicate a full sensory experience, and there are or were salons where you could be placed into a unit that provided a full sensory experience. And, I believe those operated on randomly generated sensory input, rather than input that generated the same sequence of input over and over.

I don't think that putting on headphones and listening to the same redundant sound track over and over will have a big impact on the brain, regardless of the frequencies generated through it. If anything, the brain will probably build a tolerance or lose sensitivity to the sound track over time, since it becomes redundant after a few plays. After a while, the brain becomes less conscious of things that occur frequently.

I could be completely wrong about the above, but to me, what I'm saying seems like a big flaw in the concept of this technology. I think you are better off going to the ocean, or to a loud river stream or waterfall, and allowing that experience to bring you into a deeper or more relaxed state. It certainly has worked for me in the past. Just my opinion though.