Aside from Brain Evolution, this is another good resource for brainwave entrainment products that I recommend. They have binaural beats and isochronic tones for many different applications. The nice thing is that they are inexpensive, so you can experiment with different types and find ones that work for you. They also have a membership plan that makes experimenting even more affordable. It’s probably the best bang for the buck that I can find for brainwave entrainment.
Using a small amount of alcohol in the Pregnancy and Children's lines was a conscious decision. It enables us to keep the strength and efficaciousness of the formula intact but is also gentle and appropriate for women and children. Extracts made with only glycerine or water limit the constituent profile. WishGarden's finished extract contains a minimal amount of alcohol, which, per serving, is at a very low dietary level (similar to what is found in kombucha and ripe bananas). You can also further reduce the alcohol content by stirring your droppers full, or pumps, into hot water or tea for a few minutes.
Gamma waves are the fastest brainwave frequency range. Gamma brain waves are believed to link and process information from all other parts of the brain. A high amount of gamma wave activity in the brain is associated with intelligence, compassion, focus and feelings of happiness. High levels of gamma brain waves have also been linked to improved memory and an increased sensitivity to sensory input. Low amounts of gamma brainwave activity have been linked to learning difficulties, poor memory and impaired mental processing.

The use of brainwave entrainment techniques offers many benefits for overall health and well-being, including improved emotional stability, increased cognitive function, and a deepening of creative insight. Much of this benefit derives from the hemispheric synchronization occurring as a result of entrained brainwaves. This effect happens when the electrical impulses in both hemispheres synchronized to the same frequency being delivered through the entrainment source.

All techniques, whether mantra, focus on the breath, contemplation of a koan, or any other, are simply the vehicles we use to take us into (hopefully) a meditative state. Put another way, the purpose of repeating a mantra is not to get proficient at repeating a mantra. The purpose is to take us to a meditative state where the mantra slips away and is no longer necessary.
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).
... These factors may be the specific frequency of BB; the targeted population-because it is known that older people have different quality of brainwave activity than, e.g., youngsters (Bazanova & Aftanas, 2008;Clark et al., 2004), and the tests used to detect the possible changes in working memory capacity. Based on the research showing a positive impact of alpha-range BB on cognitive functioning, specifically attention, auditory sequential memory, working memory, working memory storage, reasoning ability, cognitive processing and hemispheric synchronization, (Carter & Russell, 1993;Cruceanu & Rotarescu, 2013;Foster, 1990;Kennerly, 1994;McMurray, 2006) as well as on the wealth of research documenting the important role of alpha brain wave activity on vigilance, in-hibitory processes, attention, filtering out irrelevant information working memory, the visuo-spatial component of working memory, perceptual abilities and information processing speed (Braboszcz & Delorme, 2011;Clark et al., 2004;Engle et al., 1999a;Freunberger et al., 2011;Klimesch et al., 2007;Lachat et al., 2012;Oprisan, 2004;Palva & Palva, 2007;Rihs et al., 2007;Sauseng et al., 2009;Tuladhar et al., 2007;VanRullen & Koch, 2003), we believe that BB of a frequency that corresponds to the alpha range of brain activity has a temporary effect on working memory capacity. In our study, subjects were exposed to 9.55 Hz BB stimulation while we measured their working memory capacity through the Automated Operation Span Task (AOSPAN). ...
There are differences between high (over 18 hertz), mid (15 to 18 hertz), and low range beta states (12 to 15 hertz). Low beta states are more relaxed while still being focused, making this a good range for many daily work related tasks like balancing a checkbook, making a shopping list, or driving to a new place. However, people with attention deficit disorder lack the mental focus for doing these types of activities, and studies have found people with ADD are often low in this range of beta brainwaves.

This is probably the most popular choice of frequency. The theta state is a state of tremendous stress relief. The benefits associated with theta level relaxation include improved concentration, reduced hyperactivity and improved memory. While in a state of theta relaxation, one’s blood pressure, breathing and heart rate all slow to a much more restful and healthy level that promotes natural healing. During theta relaxation one may also experience vivid flashes of mental imagery as the mind opens to memories or subconscious information that is not available to the conscious mind during the normal waking state. The theta state is a very deep state of relaxation that is excellent for deep hypnosis and mental programming.
People who are new to meditation sometimes complain that they find it too difficult to silence their thoughts. This is perfectly normal and in fact, if you are new to meditation you should not expect to achieve absolute mental silence in the next day or two. Even the most experience meditators still have their good days and bad days when it comes to meditation and a certain amount of mental activity during meditation is quite normal.
So, what we’re doing is combining these two parts, the awakening of complete stillness and deep relaxation with the rhythmic sounds, and embedding all frequencies within the music from right at the upper limits of human hearing to the lower limits. There is multi-level entrainment within Journey—I’ve layered in everything I know about audio brainwave entrainment into this track. 
Because the brain filters and interprets reality in a split-brained way, we tend to see things as separate and opposed, rather than as connected and part of the oneness spoken of by the great spiritual teachers (and, in the last few decades, by quantum mechanical physicists). Thus, at a deep level, the dual structure of our brain, in conjunction with brain lateralization, predisposes us to see and experience ourselves as separate from, and often in opposition to, the rest of the world—instead of experiencing the elegant interconnectedness between us and everything else. Our childhood associations and programming build on this inborn tendency by training us to seek this and avoid that, to move toward pleasure and away from pain, to do good and not bad, and so on. The greater the lateralization in the brain, the greater the feelings of separation—and the greater the feelings of separation, the greater the fear, stress, anxiety, and isolation.
“Chronic stress,” however, is not so easily resolved. This type of stress is associated more commonly with negative health concerns. Chronic stress results when there are constant multiple stressors or major life stressors present (4). Money, work, and the economy were the most commonly reported factors contributing to chronic stress in the American Psychological Association’s (APA) 2011 Stress in America™ survey (3). Additional significant stressors include relationships, family responsibilities, family and personal health problems, job stability, and personal safety (3). Major events, such as the death of a loved one, divorce, and moving also can produce chronic stress.
“Binaural beats are not very noticeable because the modulation depth (the difference between loud and quiet) is 3 db, a two-to-one ratio. (Isochronic tones and mono beats easily have 50 db difference between loud and quiet, which is a 100,00-to-1 ratio). This means that binaural beats are unlikely to produce an significant entrainment because they don’t activate the thalamus.”
Binaural beats are dual tones, each one slightly different from the other. You hear one tone in each ear and your brain responds by creating a tone to reconcile the difference between the two. Isochronic tones are single tones. The variation in pattern here is brought in by interspersing silence between the sound, which means that your isochronic tone does not have a continuous sound but tones broken up by silences. Studies show that isochronic tones have far more contrast than binaural beats because of the silence and sound pattern. This sharp contrast evokes a faster impact from your brain, prompting it to match the frequency more quickly. Also, isochronic tones are found to be stronger stimulants to the brain.
Alpha is the resting state for the brain; it is “The Power Of Now”, being here in the present. The Alpha state is the relaxed state of consciousness essential to stress reduction. It is intensely pleasurable: you are awake but relaxed and not processing much information, with a sort of floating feeling. According to Alpha researcher Dr. Joe Kamiya, the Alpha state is “something like letting go of anxieties”.
way of describing it—at both theta brainwave frequencies. And then there are also 40-Hz gamma frequencies, the frequency that came through a lot when the Dalai Lama sent some Buddhist monks to have their brain waves studied as they were meditating and doing loving-kindness practices. Gamma is associated both with heightened awareness and also with loving-kindness practices, metta practices.
Changes in neural oscillations, demonstrable through electroencephalogram (EEG) measurements, are precipitated by listening to music,[20][21][22][23][24][25] which can modulate autonomic arousal ergotropically and trophotropically, increasing and decreasing arousal respectively.[26] Musical auditory stimulation has also been demonstrated to improve immune function, facilitate relaxation, improve mood, and contribute to the alleviation of stress.[27][28][29][30][31][32][27][33] These findings have contributed to the development of neurologic music therapy, which uses music and song as an active and receptive intervention, to contribute to the treatment and management of disorders characterized by impairment to parts of the brain and central nervous system, including stroke, traumatic brain injury, Parkinson's disease, Huntington's disease, cerebral palsy, Alzheimer's disease, and autism.[34][35][36]