Binaural beats can easily be heard at the low frequencies (< 30 Hz) that are characteristic of the EEG spectrum (Oster, 1973). This perceptual phenomenon of binaural beating and the objective measurement of the frequency-following response (Hink, Kodera, Yamada, Kaga, & Suzuki, 1980) suggest conditions which facilitate entrainment of brain waves and altered states of consciousness. There have been numerous anecdotal reports and a growing number of research efforts reporting changes in consciousness associated with binaural-beats. "The subjective effect of listening to binaural beats may be relaxing or stimulating, depending on the frequency of the binaural-beat stimulation" (Owens & Atwater, 1995). Binaural beats in the delta (1 to 4 Hz) and theta (4 to 8 Hz) ranges have been associated with reports of relaxed, meditative, and creative states (Hiew, 1995), and used as an aid to falling asleep. Binaural beats in the alpha frequencies (8 to 12 Hz) have increased alpha brain waves (Foster, 1990) and binaural beats in the beta frequencies (typically 16 to 24 Hz) have been associated with reports of increased concentration or alertness (Monroe, 1985) and improved memory (Kennerly, 1994).
Everyone knows stress can cause you to lose sleep. Unfortunately, lack of sleep is also a key cause of stress. This vicious cycle causes the brain and body to get out of whack and only gets worse with time. Make sure to get the doctor-recommended seven to eight hours of sleep. Turn the TV off earlier, dim the lights, and give yourself time to relax before going to bed. It may be the most effective stress buster on our list.
The various mental states of the individual are thought to take place across a varied range of frequencies, or brainwaves. By encouraging the frequency following process, entrainment is able to create positive change in the brain, through matching carefully-selected frequencies of light and/or sound. The stimulus enables the individual to access a different state of consciousness, which can be useful for a number of benefits including relaxation, anxiety management, stress reduction and more.
You know how movie characters always look themselves in the restroom mirror when faced with a tough situation? Well, giving yourself a quick pep talk in the looking glass can actually help relieve stress. “‘Mirror work‘ is done by looking in a mirror and vocally speaking positive affirmations to yourself with affectionate conviction, to release worry or to improve your self-confidence,” Whitaker says. To relieve stress in the moment, she suggests using a restroom mirror, your car’s rear-view mirror, or even a compact. “Calm your mind by saying encouraging affirmations aloud to yourself, such as, ‘I am excellent at what I do,’ ‘I’ve got this! I am amazing,’ ‘I am an asset to this company,’ or ‘I am awesome!’” she says.

There isn’t really a one-size-fits-all track or frequency range which is right for all kids while doing homework. So that does make it difficult to recommend one thing in particular, and why I have a number of tracks for studying and focus. If they have already learnt and understood the information, but are just trying to commit it to memory for a test, then I would recommend an alpha track, like the Memorization Study Aid product I have with the 10.4Hz frequency you referred to. If they are still trying to fully understand what is being taught in a workbook, then I would recommend a track that is mainly beta frequencies, like my Study Focus tracks. In the middle, I have a number of tracks which use a combination of beta and alpha wave frequencies, like Study Booster, Study Enhancer and Cognition Enhancer. The last 3 use similar frequencies but deliver the tones and brainwave entrainment effects in different ways. As we are all wired a little differently it does sometimes take a bit of trial and error, to see what method or frequency range works best for the individual. These types of tracks are made for a general audience. In an ideal world, you would hook up to an EEG and see in real time exactly what a person responds to best, depending on the goal and current state of mind.

Many of our common symptom-soothing formulas are designed to take effect within 5-10 minutes if used properly. To get these fast-acting results, we recommend 3-4 droppers full, or 6-8 pumps, per use to start. If you are not yet feeling the full effect within the first 5 minutes, repeat the original serving. You can do this up to 4 servings back to back. Note that some of our formulas are tonics and are meant to work over longer periods of time.
We are all unique and herbs can work differently for different people. The usage instructions on the label are written to be applicable to a general population. However, that doesn't mean they are optimum for you and the discomforts you are experiencing (small vs. large body types for example). "As needed" means you should take the amount listed at a needed frequency until you feel the desired effect (paying attention to any maximum or frequency limitations listed).
So if you are interested in using brainwave entrainment music in your own recording, do so with the knowledge that it can only help to improve the quality of your work. But please don’t feel as though your recordings will be insufficient without it (some people do worry about this - unnecessarily). My advice is that if you ever find yourself in a situation where the music you love the most is not available with brainwave entrainment frequencies, don’t ignore your intuition and discard that music. When you find that piece of music that brings your recording to life, go with it whether it has brainwave entrainment frequencies or not. The quality and feel of the music itself are the most important factors.
But the question is: Does it have a special effect on the brain? A lot of people think so. The basic claim being made for binaural beats is "resonant entrainment". Entrainment, in physics, is when two systems which oscillate at different frequencies independently are brought together, they synchronize with one another, at whatever the combined system's resonant frequency is. Examples of entrainment occur in animals in nature; for example the chirping of crickets or the croaking of frogs. Synchronization of menstrual cycles in women is another example. Even people coming together and dancing with one another is a type of entrainment. The basic claim for binaural beats is that the perceived low-frequency beat will entrain your brain wave pattern, thus forcing your brain into some desired state.
One RCT (n=108) showed significant reduction in anxiety from a single session of alpha/delta therapy for day surgery patients. A crossover RCT of a single session of theta stimulation in four healthy adults reported significant improvement from the intervention in one of five measures. Five pre/post studies reported significant benefit from the intervention for 16 of 27 outcomes.

As to the second question raised in the above paragraph, audio with embedded binaural beats alters the electrochemical environment of the brain. This allows mind-consciousness to have different experiences. When the brain is entrained to lower frequencies and awareness is maintained, a unique state of consciousness emerges. This state is often referred to as hypnogogia "mind awake/body asleep."  

Making time for connecting with the people around you, spending time outside and doing things you love with family, friends and your spouse are all stress relievers that are good for your health in many ways. Social connection is tied to longevity, since it helps people feel like they’re a part of something larger than themselves and helps give them perspective. Being outdoors has some similar effects, reminding people that they’re one piece of a much larger universe, lifting their moods and making it easier to get good sleep. (12)

Effects on cortisol: The hormone cortisol is commonly associated with stress, and when levels are higher than usual, it can have a negative impact on the body. High levels of cortisol can lead to a range of conditions, including Cushing syndrome, menstrual cycle and female libido changes, anxiety, and depression. Dr. Giampapa noted a reduction of cortisol of up to 70-80 percent in several study participants.
^ Trost W. and Vuilleumier P., Rhythmic entrainment as a mechanism for emotion induction by music: a neurophysiological perspective. In The Emotional Power of Music: Multidisciplinary Perspectives on Musical Arousal, Expression, and Social Control, Cochrane T., Fantini B., and Scherer K. R., (Eds.), Oxford, UK: Oxford University Press; 2013, pp213–225.