♥ I admit that I do not know much about brainwaves and can be swayed by suggestion (ah, the fickle subconscious), but since using this machine and sort of hiding the noise with other sounds or my own music so it is not so obvious to me, it has helped me get through my email correspondences and other online tasks with the focus that I need. Thank you so much for making this!
Cortisol is an arousal hormone, stimulating alertness and attention. Cortisol levels rise and fall in connection to circadian rhythms—cortisol levels rise to their peak levels first thing in the morning, just in time for you to be active for the day. Too-high cortisol levels are associated with insomnia, as well as more time spent in light sleep, rather than deep sleep.
From the deepest, sincere, compassionate, and loving part of my soul; I offer thank you. : ) By saving me, I believe your organization did a service to society as a whole, for now I am like a ripple in a pond that will reverberate good vibes to all who I come into contact with. I express compassion, understanding, and knowledge to all who I see need your life saving, and healing product. Like a missionary I desire to spread it; for it is pure, good and loving to my fellow man.
A binaureal beat is created by playing a different tone in each ear, and the interference pattern between the slightly differing frequencies creates the illusion of a beat. It's intended to be heard through headphones, so there's no cross-channel bleed across both ears. Listen to this, I'll play a simple binaural beat, and I'll slide the pan control back and forth from one ear to the other. You can see that there isn't actually any beat, it's just an acoustic illusion:
Binaural beats are auditory brainstem responses which originate in the superior olivary nucleus of each hemisphere. They result from the interaction of two different auditory impulses, originating in opposite ears, below 1000 Hz and which differ in frequency between one and 30 Hz (Oster, 1973).For example, if a pure tone of 400 Hz is presented to the right ear and a pure tone of 410 Hz is presented simultaneously to the left ear, an amplitude modulated standing wave of 10 Hz, the difference between the two tones, is experienced as the two wave forms mesh in and out of phase within the superior olivary nuclei. This binaural beat is not heard in the ordinary sense of the word (the human range of hearing is from 20-20,000 Hz). It is perceived as an auditory beat and theoretically can be used to entrain specific neural rhythms through the frequency-following response (FFR)--the tendency for cortical potentials to entrain to or resonate at the frequency of an external stimulus. Thus, it is theoretically possible to utilize a specific binaural-beat frequency as a consciousness management technique to entrain a specific cortical rhythm.  
You may recognize the "binaural recording" from ASMR, where the technique is often used. This explains why, if you search for "binaural" on YouTube, you get a mixture of two entirely different kinds of results: binaural beats and binaural ASMR recordings. It gets especially confusing in that there's some questionable and/or unexplored science surrounding each one.
But what would be the point of generating a beat that was at the same rate as a certain brainwave frequency? First, consider that these frequency bands relate to different states of awareness. Delta is seen in deep sleep, theta in lighter stages of sleep, alpha when we are relaxed with eyes closed, and beta when we are awake and alert. Second, the main idea behind using binaural beats to help a person relax and sleep is that of entrainment. Entrainment means that a biological process is matched to some external stimulus. For example, our circadian clock is entrained to the day/night light cycle and helps the body organize physiological processes in an appropriate way over the course of the day. A repetitive sound at the frequency of a certain brainwave band could theoretically cause the brain waves to be entrained to that frequency and thus help induce the state associated with that brainwave band. This could have therapeutic utility.

Today we're going to put on our headphones, kick back in the beanbag, and get mellow to the soothing sounds of the latest digital drug: binaural beats. These computer generated sound files are said to massage your brain and produce all sorts of effects, everything from psychedelic experiences to behavior modification. Let's point our skeptical eye at the science of binaural beats, and especially at some of the claims made for them.

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