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.
The reason this rule of thumb is so useful is because there is a huge market for simple answers. A genuine elegant solution (one that accomplishes more with less) is highly valuable in the marketplace. We are used to technology delivering new easy solutions to previously difficult tasks. While most improvements are incremental, there are occasional breakthroughs that transform our lives.
“Stress and sleepless nights are closely linked,” Buenaver says. “If you’re in pain, tend to worry, or are coping with a difficult situation in your life, you may have more stress hormones than usual circulating in your body. A poor night’s sleep adds even more. And those hormones may never be fully broken down. It’s like running an engine in fifth gear all the time.”
Another common misconception is that entrainment is going to force your brain into doing something beyond its native capabilities, or at least beyond what it is accustomed to doing. This mistaken belief is often the root that leads to comments like, “When I meditate with LifeFlow my face gets flushed (or my hair vibrates or I develop x-ray vision, or any of the other things we come across). If I meditate without LifeFlow the face flushing doesn’t happen. LifeFlow must be causing it.”
Joe:             The Journey  soundscape took a lot of work. I wanted to bring in the very best of what I knew about brainwave entrainment and to make the best brainwave entrainment product—with the best entrainment technology—that I possibly could. So, there are all sorts of things going on in Journey  to provide a sound bed to support the experience of expansiveness and also communicate elements of the heart-based work I talked about earlier. (See part I of this interview, A Guide to Transpersonal Meditation.)
Recent research at the University of Lisbon finally uncovered the reason for the 350 year-old mystery, finding that the resonance of sound is the mechanism for entrainment of swinging pendulums and ticking clocks, and it seems likely that the energy transferred by sound is also responsible for other observations of entrainment, including brainwave entrainment.
With its focus on full, cleansing breaths, deep breathing is a simple yet powerful relaxation technique. It’s easy to learn, can be practiced almost anywhere, and provides a quick way to get your stress levels in check. Deep breathing is the cornerstone of many other relaxation practices, too, and can be combined with other relaxing elements such as aromatherapy and music. While apps and audio downloads can guide you through the process, all you really need is a few minutes and a place to stretch out.

Basically, "two ears." One usage of the word is "binaural recording," which is a form of stereo recording meant to take advantage of the spatial perception of the human ear. Recordings are usually done using a pair of microphones mounted to a dummy head with roughly accurate models of the human outer ear, and the result when played back through headphones is extremely realistic and comparable to surround sound, though following an entirely different recording model. Binaural recordings aren't woo at all, and have nothing to do with binaural beats.[citation needed]
Participants in the included studies were children and adults, either healthy or with conditions such as learning disabilities, attention deficit hyperactivity disorder, migraine, stress, anxiety and myofascial pain. Interventions included single, alternating, ascending or descending frequencies of photic or auditory stimulation or audiovisual entrainment selected either by the participant or by the investigator. Nearly half the studies used single sessions and the rest used multiple sessions ranging from nine to 100. Length of session varied from 0.5 seconds to 60 minutes. Frequency of session varied from twice daily to weekly. Outcomes reported in the review included cognition (including verbal skills, performance skills, attention, memory and overall intelligence/achievement), short- and long-term stress, pain, headache/migraine, mood, behavioural problems and premenstrual syndrome (PMS).
When blended with musical sounds, brainwave entrainment frequencies induce specific states of mind, which are the result of those brainwaves, delivering them in pleasing and relaxing audio tracts for use with and without stereo headphones. For example, alpha and theta waves, because they exist at the borders between conscious and unconscious thought, are especially rich and useful for tapping into and stimulating subconscious processes.
When we first use brainwave entrainment, we may not have anything specific in mind that will happen, but we hold a general expectation that “something” should happen. As we begin the process of entrainment we are on high alert looking for any little indication that something is happening. Pretty soon we identify some feeling or twitch or unusual perception. The moment we focus on whatever it is, the act of focusing on it magnifies the thing. Since we were already viewing the situation with an expectation that it was the entrainment that was going to produce some sort of result, we automatically associate whatever our phenomenon is with entrainment.
Theta brainwaves in the frequency range of 6 to 9 hertz are known as thalpha waves because of their proximity to alpha waves. They are seen during states of high suggestibility, during hypnosis, and during paranormal experience and are also connected to an increase in human growth hormone (HGH) levels and higher blood flow to the brain. Theta brainwaves sit between the realms of the subconscious and conscious mind, making them an especially useful brainwave state for developing creative thinking, working through emotional problems, and integrating subconscious and conscious experience. 
A more extensive study of over 100 participants who were undergoing general anesthesia for a day procedure, reported a decrease in pre-operative anxiety. The participants in this study listened to 30 minutes of binaural beats before surgery, but the researchers noted that people experiencing high levels of pre-operative anxiety could listen to binaural beats for up to 1 hour before anesthesia to reduce levels of anxiety.
A study published in Electroencephalography and Clinical Neurophysiology by Paul Williams and Michael West in 1975 examined the brainwave states of people experienced in meditation while using photic stimulation, and another study by Leonard, Telch, and Harrington in 1999 examined the successful use of brainwave entrainment techniques for attaining meditative states in subjects.
You have three Theta options. First, you can begin with the 30 minute Alpha Light Meditation, then do the 30 minute Theta Deep meditation that is in the same folder with the Alpha track. This is the most gentle way to introduce yourself to the Theta meditations, as these two tracks are designed to work with each other. This Theta track must be used after the Alpha track, because it begins with the same frequency where Alpha ends.

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]