Binaural Beats or “binaural tones” are created by playing slightly different frequencies separately into each ear. The difference between the two frequencies stimulates a response in the brain which correlates with this frequency difference. For example, if we present a 100 Hz tone to the left ear and a 105 Hz tone to the right ear, a frequency of 5 Hz is stimulated. This is what is known as the “frequency following response”.
And so we (not too surprisingly) begin to experience “symptoms” or “signs” of something that we do not ordinarily experience. Immediately, we associate these with the entrainment or the meditation. We wonder if this is something real or imagined so we often start asking others if they have experienced the same or similar things. We seek validation that our practices are producing tangible effects on us.
Therefore we are very receptive to new technology products that promise to improve our lives, or solve previously difficult problems, because of some new scientific or technological advance. This has created, in a sense, a marketplace of consumers that expect to be dazzled with technobabble they don’t understand, backed by assurances of legitimacy by the citing of research and association with professionals or professional institutions, and offering significant benefits. We are all, in a sense, waiting for that next product to improve our lives, and many of us like to feel we are on the cutting edge – getting an advantage over others by being savvy early adopters.
Delta brain state is related to the unconscious or super-conscious mind. Delta waves are the slowest of all five brainwave frequencies. These brain waves are generated in deep sleep and in very deep meditation. In the sleep cycle, the deepest of sleep states is called “Slow Wave Sleep” (SWS). In this phase, the brain begins producing very slow, large Delta waves. The deeper the sleep, the higher the amount of delta waves. This stage plays a vital role in health and well-being, especially because healing and regeneration processes are stimulated in this state. In the Delta state, you do not dream, you are completely unconscious.
It's a scenario played out every evening all over the country: Come home from work and start venting to your spouse or roommate about your day. Instead of creating a negative atmosphere the minute you walk in the door, try starting off the evening with your family or friends by exchanging good news. Something good every day, you just need to recognize it.
Most of these websites give some brief explanation of entrainment. The example you hear most often is that of Dutch polymath Christiaan Huygens, who in 1665, hung two pendulum clocks next to each other on a wall. He noticed that the pendulums eventually matched each others' frequency, but always in antiphase, opposite to each other, as if canceling each other out. He'd try disturbing one or setting them in sync, but they'd always return to the same antiphase synchronization. Huygen's experience is widely touted on binaural beat websites as a demonstration of how systems can become spiritually connected through some energy field. However, they misunderstand what happened, and have not read the full story. Huygens also tried taking one clock off the wall, and as soon as they were no longer physically connected to one another via the actual wall, the effect disappeared. It was not the proximity of the clocks to one another that created the entrainment; it was their physical, mechanical connection to one another. As each pendulum swung it imparted an infinitesimal equal and opposite reaction to the wall itself. With two clocks on the wall, the system naturally sought the lowest energy level, according to the laws of thermodynamics; and both pendulums would thus swing exactly counter to each other, minimizing the system's total energy.

“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.
Living in a Mindful Universe relates the emerging view of consciousness that is revolutionizing the scientific community, and is, in many ways, the continuation of Dr. Alexander’s journey since writing Proof of Heaven. This journey parallels an unprecedented shift in the western scientific paradigm that, when fully incorporated, will lead to far more meaning and purpose in our lives.
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.

a past history of trauma. When faced with stressful situations, you may find yourself totally stuck and unable to take action. Your challenge is to break free of your “€œfrozen”€ state by rebooting your nervous system and reactivating the body’s natural “€œfight-or-flight”€ stress response. Physical movement that engages both your arms and legs, such as walking, swimming, running, dancing, climbing, or tai chi, can be particularly helpful. As you move, focus on your body and the sensations you feel in your limbs rather than on your thoughts. This mindfulness element can help your nervous system become “unstuck” and move on.
Some research suggests that the benefits from brainwave entrainment can last a lot longer, and still be seen for some time after you've stopped using it.  Study participants have still maintained improved test scores a few weeks after the stimulation had ceased.  Research on the long-term benefits has so far been minimal though, so how long the effects last is still up for debate.
Delta (3hz – 0.2hz) – Deep, dreamless sleep. Intuition. Empathy. Brainwave expert Judith Pennington calls it the doorway to Universal Consciousness and “A radar that scans the environment and psychically picks up information and energy.” According to British physicist C. Maxwell Cade “There have been reports that delta waves appear at the onset of paranormal phenomena.” (More information can be found in Cade’s book The Awakened Mind)
“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.
Why not? Because the flushing has nothing to do with the brainwaves or entrainment, and everything to do with the expectations we bring to the use of entrainment. We didn’t watch that sunset with any expectations of face flushing. We didn’t have any of those expectations while listening to that music. In short, there is a cause generating the effect, but the cause is our expectations, (excellent Article here) not the entrainment.

The effects are strongest while you are listening to the tones because your brainwaves are synchronized and tuned into the frequency range you desire at that time.  After you've stopped listening the effects can still linger for a while afterwards.  The timescale will vary from person to person and be affected by what you do after you've stopped listening.
A popular opinion in the brainwave entrainment community is that listening to isochronic tones without music produces a much stronger effect.  However, in the study by Doherty, Cormac. “A comparison of alpha brainwave entrainment, with and without musical accompaniment” (2014),  it was concluded that brainwave entrainment was equally effective for isochronic tones, both with and without music.
For example, if a 530 Hz pure tone is presented to a subject's right ear, while a 520 Hz pure tone is presented to the subject's left ear, the listener will perceive the auditory illusion of a third tone, in addition to the two pure-tones presented to each ear. The third sound is called a binaural beat, and in this example would have a perceived pitch correlating to a frequency of 10 Hz, that being the difference between the 530 Hz and 520 Hz pure tones presented to each ear.
♥ ← This set of tones with the bird calls from Aotearoa is keeping me awake while I finish an essay I've been working on for the past four days. Focus beats + sounds I associate with morning = wakefulness. Still craving the bed, but at least I'm not falling asleep at my desk. Thanks myNoise, without you I'd probably be listening to music and distracted.
While a practical understanding of brainwaves has been around for as long as people have been singing, chanting, and drumming, a scientific view of the electrical activity inside the human brain was not published until 1924 when German psychiatrist Hans Berger developed a machine for sensing and recording activity in the brain by attaching small electrical sensors to the scalp of his patients and recording the resulting electrical activity. Berger’s inventions and discoveries were built upon the earlier work of Richard Caton who published animal studies on brainwave oscillations in 1875.
In one study, researchers had a group of participants relax alone in a quiet, low-light environment following an exercise session. They split the group in two — one spent 20 minutes listening to theta-frequency binaural beats while the other listened to a carrier tone and monitored their parasympathetic (rest and relaxation) and sympathetic (fight or flight) nervous system activity. Researchers found the group that listened to binaural beats experienced an increase in parasympathetic activity and a decrease in sympathetic activity, along with higher rates of self-reported relaxation.

For example, exercise and perusing a goal very ambitiously are both types of stress, except they ultimately benefit the body. Areas of the brain, including the hippocampus, amygdala and prefrontal cortex can pick up on positive stressful experiences and cause “stress-induced structural remodeling” of the brain, which means you experience alterations in behavioral and physiological responses to these positive events. The result is that in the future you’re better able to handle similar situations because you learn from them, associate them with a reward and stop perceiving them as threatening.
The Neuro Programmer website, as is typical, is full of testimonials and vague references to research. I tried to track down the research they referenced, but could not find anything published or peer-reviewed by the authors named or on the subjects indicated. For example, they cite one study by Thomas Budzynski, but the only thing published by him that is listed on Pub Med is a small study on biofeedback published in 1969. The 1999 study they reference is not listed. Also – Budzynski has connections to another company – Theta Technologies – which sells similar technology.  (The exact nature of his connection is not clear, he was at least a consultant. He is also listed as the director of research for another company, Synchromed, LLC.)  This looks like just another in-house worthless study to support the marketing of a product.
In 1956, the famous neuroscientist W. Gray Walter published the results of studying thousands of test subjects using photic stimulation, showing their change in mental and emotional states. He also learned that photic stimulation not only altered brainwaves, but that these changes were occurring in areas of the brain outside of vision. In Walter’s words:
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.
As with meditation, mindful exercise requires being fully engaged in the present moment, €”paying attention to how your body feels right now, rather than your daily worries or concerns. In order to “€œturn off”€ your thoughts, focus on the sensations in your limbs and how your breathing complements your movement, instead of zoning out or staring at a TV as you exercise. If you’€™re walking or running, for example, focus on the sensation of your feet touching the ground, the rhythm of your breath, and the feeling of the wind against your face. If you are resistance training, focus on coordinating your breathing with your movements and pay attention to how your body feels as you raise and lower the weights. And when your mind wanders to other thoughts, gently return your focus to your breathing and movement.
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]