♥ 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!
At Gaia Meditation, most of audio programs including free relaxation music, free sleep music, free meditation music etc. use the technology of brainwave entrainment (or “brainwave synchronization”) with powerful binaural beats and isochronic tones. Our audio tracks utilize pure and precisely tuned sound frequencies which will drive your brain activity (consciousness) into your desired state: Gamma, Beta, Alpha, Theta or Delta.
Different people have different requirements when it comes to frequency changes in the music and it's quite impossible for us to anticipate them all. We would need to produce so many different variants of all our music productions that it would be impractical to manage and confusing for our customers. For example, if we were to start raising the frequency from theta up to alpha between the 50-60 minute mark of a piece of music, this would be useless to someone who used the music for a guided meditation that was only 45 minutes long. In the early stages of the development of our brainwave entrainment music we had so many different requests from different people that we could only opt for the simplest solution, which is to use a consistent frequency throughout. It might not be the absolute "perfect ideal", but this is still a very effective technique and the feedback we've received on our brainwave entrainment music has always been exceptionally positive.
In the 1980s, a researcher in Japan, Tsuyoshi Inouye described how light stimulation creates synchronization of brain hemispheres. Since then, other researchers have detailed the positive effects of hemispheric synchronization including a 1984 study by researcher Dr. Gene W. Brockopp stating that hemispheric synchronization resulted in improved intellectual functioning as well as improvements in long-term memory, and these effects are cumulative over time.

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]

If you can't spend a full hour in meditation, try the 30 minute Theta Standalone Meditation. This track takes you a little deeper into exploring the Theta frequency than the first Theta track, so it can also be a progression if you have used the first Alpha/Theta combination. If you do have a full hour for Theta, use the 60 minute Theta Standalone meditation.
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. 
Most programs start at a work/life busy brain Beta frequency of twenty light flashes per second (20Hz) and slowly ramp them down to Alpha (relaxation and meditation) at 8-12 HZ, Theta (deep relaxation and dreaming) at 4-8 Hz) and Delta (dreamless deep relaxation) of .5-4Hz. We have taken measurements at Mass General with state of the art EEG equipment and have seen a slowing of the brain waves from Beta to Theta in two minutes and complete brain wave harmonization in the left, right, anterior, posterior and occipital regions of the brain.
Hi EJ, at the moment, there hasn’t been any research to give an indication of how long you should or shouldn’t listen for. Over time, I’ve seen people use my tracks for longer and longer. I started off providing 30-minute study tracks, but through demand, I extended them to 3-hours. I know from the many thousands of comments I’ve had on YouTube that a large number of people play those 3-hour tracks on repeat, or listen to different ones, one after the other throughout the day. I’ve also seen apps where you can play tracks like mine on continuous repeat. So it’s common for people to listen to them all day while they are studying.
Beta: These brainwaves are associated with high levels of alertness and arousal. When beta brainwave patterns dominate, we’re primed to focus and concentrate, to make decisions and think analytically. When you’re analyzing an issue at work, you’re probably in a beta-dominant state. Beta waves are fast, with a higher frequency (between 15-40 hertz). At the higher levels of this range, beta waves are associated with anxiety.

Stressed out after work? Need to relax and be focused before a test, exam, or interview?. This CD is for you. Wish I could explain how this CD works on your brain's "entrainment" but they do enclose a benefits description inside the CD case. It's amazing to listen to and see/feel the results after hearing the entire CD with a quality set of headphones on. Note: also works well with earbuds. I couldn't tell if the last track had played or not on the Nexus 6p...it just takes you away then brings you back ... into something more structured and coherent.

“One of the best ways to explain how brainwave entrainment works is by observing the effect of a tuning fork on a guitar string,” says Naik. “Hit a tuning fork tuned to a particular sound frequency, such as the note C, and hold it close to the strings of a guitar. You will notice that the C string on the guitar starts to vibrate because it has entrained on to the same frequency of the tuning fork.”

_{It is important to note that not all stress is bad. Everyone experiences a certain amount of stress on an almost daily basis, and it cannot be completely eliminated. Stress becomes a problem when too much is experienced, and it has a negative impact on behaviors, relationships, and health. The term “eustress” refers to positive stress that is associated with improved performance and productivity. “Distress” is negative stress that is associated with performance decrement and negative health consequences. The individual’s perception of the stressor and coping resources determine whether a situation is eustress or distress. College graduation is a stressor for most. The student who has a job or who has been accepted to a graduate program likely perceives the stress of graduation as eustress, whereas the student who has student loans and no immediate plans of a job or further education perceives distress.}
Science shows that massages reduce stress, but you don’t have to go to the spa—you can give yourself one right now. “Learning how to self-massage your foot, head, neck, or shoulders reduces the stress hormone cortisol, boosts your immune system, and increases the feel-good hormones oxytocin, dopamine, and serotonin,” Dr. Serani says. You can even use a tennis ball or cold water bottle on your feet or neck. In addition, try rubbing pressure points like the webbing between your thumb and index finger, or your inner wrist. Another technique is the EFT tapping technique, literally tapping certain points on your body such as in between your eyes, your temples, and the center of your collarbone. “Tapping brings cleansing energy to the meridian points, as your mind directs the energy to what’s unbalanced in the body,” Whitaker says. “This restores your mind and body’s natural balance, which aids in releasing stress, worry, fears, and disharmony.”
There are general recommendations for stress management that can be applied in most situations. However, keep in mind that there are individual differences and preferences, so a “cookie cutter” approach should be avoided when making recommendations. A comprehensive stress management program will include specific techniques prescribed on an individual basis, but general stress management recommendations are presented in Table 2.
^{Gamma was dismissed as 'spare brain noise' until researchers discovered it was highly active when in states of universal love, altruism, and the ‘higher virtues’. Gamma is also above the frequency of neuronal firing, so how it is generated remains a mystery. It is speculated that gamma rhythms modulate perception and consciousness, and that a greater presence of gamma relates to expanded consciousness and spiritual emergence.}
We may use the term “to meditate” as a convenience, but always keep in mind, what is really meant is that we enter into a state of meditation. It’s an important point to distinguish because if we get caught in the trap of regarding meditation “as a verb” it leads into all sorts of problems and misunderstandings. If a person incorrectly believes meditation is a verb, they generally also confuse whatever technique they use to arrive at a state of meditation as being meditation in and of itself.
Brainwave entrainment is a colloquialism for such 'neural entrainment', which is a term used to denote the way in which the aggregate frequency of oscillations produced by the synchronous electrical activity in ensembles of cortical neurons can adjust to synchronize with the periodic vibration of an external stimuli, such as a sustained acoustic frequency perceived as pitch, a regularly repeating pattern of intermittent sounds, perceived as rhythm, or of a regularly rhythmically intermittent flashing light.