Going deeper into a trance-like state of meditation, you enter the mysterious Theta state where brain activity slows almost to the point of sleep, but not quite. Theta is one of the more elusive and extraordinary realms you can explore. It is also known as the twilight state which you normally only experience fleetingly upon waking, or drifting off to sleep.

In order to understand brainwave entrainment you first have to understand something about brain waves and electroencephalograms (EEG). Neurons are cells that communicate with each other through electrical conduction. When a neuron fires it creates a small electrical and magnetic field. These fields are far too small to measure by placing electrodes on the scalp, or even on the surface of the brain. The only reason we can detect the electrical fields of the brain is because many neurons are firing together – in synchrony. All brain waves that are measured by an EEG, therefore, represent a large group of neurons firing together.
“When you play two separate frequencies in each ear, say 140 Hz and 149 Hz, the difference in frequency is 9 Hz. Your brain compensates for this difference, and a third tone of 9 Hz is experienced,” says Niraj Naik, founder of Trpynaural, a resource for binaural tracks. “This will result in your brain being raised or lowered and tuned into the desired frequency. This is how binaural beats are produced.”

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."  

Binaural beats are the playing of two sine waves of close, but not the same, frequency into different earpieces of a set of headphones. The "beat" is heard as the brain tries to process them as a distinct sound, while taking into account the constructive/destructive interference. It is said to migrate brain waves to be closer to that frequency, like a sort of biological resonance, which is true. Of course the same can be said for listening to relaxing music help you relax, up tempo music to help you feel energetic, etc...
What the Neuro Programmer does (as far as I can tell – access to much of the website requires the purchase of product) is present sound and visuals on the computer screen. The user is meant to passively view and listen to this while their brain is effortlessly programmed to solve whatever problem they are having or improve whatever performance they are interested in.
Entrainment is a phenomenon seen is a wide variety of different natural circumstance. In the field of chronobiology, the study of biological rhythms in living organisms, entrainment is the synchronization of a circadian rhythm with the rhythm of an external pattern, such as the synchronizing of women’s menstrual cycles with the phases of the moon or with one another in a group.

There is also evidence to suggest meditation plays a protective role against the natural reduction in grey matter volume associated with aging. One study found evidence that Zen meditators experienced a slower age related decline rate for cerebral gray matter volume in the putamen which plays a role in learning, cognitive flexibility and attentional processing [14] This could suggest a better attentiveness in aging meditators versus non-meditators.
Joseph Kao, creator of Profound Releasing, Profound Renewal, and Sound Asleep, is a hypnotherapist and a solution-focused therapist with a private practice in Cambridge, UK. Joe was the co-developer of an acclaimed course on conversational hypnosis, and he regularly teaches hypnotherapy and psychotherapy to other therapists. He has also been the head scriptwriter for over 800 professional hypnotherapy recordings. Joe was drawn to the world of philosophy, meditation, and brainwave entrainment technology from an early age, and he’s had a daily meditation practice since 1998.
“A quite different phenomenon results when stereophonic earphones are used and the signals are applied separately to each ear. Under the right circumstances beats can be perceived, but they are of an entirely different character. They are called binaural beats. . . . Binaural beats require the combined action of both ears. They exist as a consequence of the interaction of perceptions within the brain.”
Hello my name is Arvinder I really hope and pray u can help me I am really struggling I am 46 had serious insomnia aafter glandular fever at 23 since then been on all sorts of meds in the world for sleep five years back I did hypnosis while on the meds I felt really messed up and struggled to live I was on antipsychotic and sleep meds I tried to correct that mess and many many hypnosis sessions then I ended up on internet and listened to a deep sleep binaural beat music almost three years ago firer to

Similar results have been achieved with the use of music alone, the most famous example being the so-called Mozart effect. In his book "Pourqui Mozart?" Dr. Alfred A. Tomatis claims that the composer’s music promoted healing and brain development[1]. The idea has been further popularized by Don Campbell in his book "The Mozart Effect", which claims that listening to Mozart can temporarily boost a person’s scores on portions of an IQ test [2].
After one month of using Equisync, I feel relaxed, calm and not stressed at all, despite that I am leaving my present job soon for an early retirement, I handle the situation very well. I have the feeling that I’m going to be ok and there is nothing to worry about. This is what I have gained so far from using Equisync and it’s really meaningful in the erratic world that we live in.
I forgot to tell you, after using your meditation for a few weeks, I woke up one morning with the most vivid recollection of having an out of body experience […shortened…] I am hoping to experience this again and control myself the next time. Thank you for enabling me to remember this extraordinary experience. I never believed they were real until I used your program.

Did you ever wonder why someone who "has everything" could be depressed and unhappy and why someone who has very little can be so happy? Of course, we can answer that material wealth, beauty, situation, good environments aren't everything. (Sure are nice though :+)) But that explanation ends up seeming like a rationalization and not an explanation. Consider the idea that the answer could reside in our brainwaves. Certain brain frequencies promote a feeling of well being and certain frequencies promote a feeling of depression. The state of our brainwaves also influences our tendency to be overly reactive or detached.

Theta waves have a frequency between 4 and 7.5 hertz, making them slower than more wakeful alpha but faster than the dreamless slumber of delta. Theta brainwaves are the frequencies of nighttime dreams and REM sleep when the brain goes through bursts of activity and eye movement. People also experience theta waves in a state of light sleep, deep relaxation, during meditation and prayer, and when daydreaming. Theta waves produce an experience of inward wakefulness where we become disengaged from the outside world while engaging in inner activity. At the lower frequencies of theta, sleeping states are experienced, and at the higher range of frequency, awake relaxed states are experienced. 
When you play a tone with a slightly different frequency into your left and right ear — say, 200 hertz (Hz) in one and 210 Hz in the other — they travel separately to your inferior colliculus, the part of your brain that gathers auditory input. There, the tones “squelch” together into a so-called “beat” at a perceived new frequency. (In this case, it would be 10 Hz.)
For example if you play a tone of 200hz in the left ear, and a tone of 190hz in the right ear (with the difference being 10hz) a beating tone will be perceived at 10 hz which is the binaural beat. What ever the difference is between the tones coming into the ears (in this example the difference is 200hz-190hz=10hz) the binaural beat will be that difference.

With almost 100 years of research validating the effectiveness of brainwave entrainment, it’s no wonder why it’s used by thousands of people all over the world. What does the future entail in this exciting field? With the adoption of smartphones, virtual and augmented reality, and advancements in technology reducing the cost of EEG and other forms of biofeedback devices, the entrainment possibilities are endless.
Your brain operates at certain levels of activity – the normal waking, active Beta, the meditative Alpha, the asleep-and-dreaming or deep meditative Theta, and the deep sleep/unconscious Delta. Beta is characterized by one thing we all want to get away from – stress.But that brainwave state has its place. It’s the action mode, and that’s the way it should be! If we’re not alert when we’re awake, bad things can happen, right?
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.

In 1973, biophysicist Dr. Gerald Oster published a famous article in Scientific American titled “Auditory Beats in the Brain”, which found that when two pure tones of varying frequencies were combined, a third rhythmic beat was created which he called binaural or monaural beats. According to Oster, monaural beats occur when two tones are combined and sent through a loudspeaker, while binaural beats occur when stereo headphones are used to deliver each tone separately to each ear. Oster concluded that monaural beats were a more effective form of brainwave entrainment.
Do note the pre-sets slightly below to the right. Remember: Delta is for deep sleep. Theta is associated with dreaminess. Alpha is a blank or relaxed state of mind and Beta is when you’re active. Try to clear your mind of any thoughts and expectations, and set the volume to an acceptable level. You can play around, but try to give a minute or two for your state of choice. At first glance, you’d think this sounds like an alien spaceship, if not a microwave or a washing machine. Whatever it sounds like to you, if you give it an open mind you will notice there is something weird about this after all. Hopefully, your chosen frequency will have guided you towards the intended effect!

Research done under Gerald Oster suggested that binaural beats may be used as a medical tool, especially for diagnosing neurological conditions. In particular, he noticed that untreated sufferers of Parkinson’s disease were unable to “hear” binaual beats but further research indicated successful treatment when the subject was finally able to perceive them at the end of a Parkinson’s treatment regimen. Oster also noted difference in perception in women based on their menstrual cycle, and posited that there may be some connection between the ability to perceive binaural beats and the woman’s levels of estrogen at the time.

Electroencephalography (EEG) has been used in many studies as a primary method for evaluating the meditating brain. Electroencephalography uses electrical leads placed all over the scalp to measure the collective electrical activity of the cerebral cortex. Specifically, EEG measures the electric fields of large groups of neurons. EEG has the benefit of excellent temporal resolution and is able to measure aggregate activity of portions or the entire cortex down to the millisecond scale. Unlike other imaging based methods, EEG does not have good spatial resolution and is more appropriately used to evaluate the running spontaneous activity of the cortex. This spontaneous activity is classified into four main classifications based on the frequency of the activity, ranging from low frequency delta waves (< 4 Hz) commonly found during sleep to beta waves (13–30 Hz) associated with an awake and alert brain. In between these two extremes are theta waves (4–8 Hz) and alpha waves (8–12 Hz).
"Spontaneous wandering of the mind is something you become more aware of and familiar with when you meditate," continues Ellingsen, who is an experienced practitioner. "This default activity of the brain is often underestimated. It probably represents a kind of mental processing that connects various experiences and emotional residues, puts them into perspective and lays them to rest."
Similar results have been achieved with the use of music alone, the most famous example being the so-called Mozart effect. In his book "Pourqui Mozart?" Dr. Alfred A. Tomatis claims that the composer’s music promoted healing and brain development[1]. The idea has been further popularized by Don Campbell in his book "The Mozart Effect", which claims that listening to Mozart can temporarily boost a person’s scores on portions of an IQ test [2].
You may recognize the "binaural recording" from ASMR, where the technique is often used. This explains why, if you search for "binaural" on YouTube, you get a mixture of two entirely different kinds of results: binaural beats and binaural ASMR recordings. It gets especially confusing in that there's some questionable and/or unexplored science surrounding each one.

Beta waves range between 13-40 HZ You are wide-awake, alert. Your mind is sharp, focused. It makes connections quickly, easily, and you're primed to do work that requires your full attention. In the Beta state, neurons fire abundantly, in rapid succession, helping you achieve peak performance. New ideas and solutions to problems flash like lightning into your mind.

Slightly higher-frequency entrainment can lead to hyper suggestive states of consciousness. Still higher-frequency EEG states are associated with alert and focused mental activity needed for the optimal performance of many tasks. Perceived reality changes depending on the state of consciousness of the perceiver (Tart, 1975). Some states of consciousness provide limited views of reality, while others provide an expanded awareness of reality. For the most part, states of consciousness change in response to the ever-changing internal environment and surrounding stimulation. For example, states of consciousness are subject to influences like drugs and circadian and ultradian rhythms (Rossi, 1986; Shannahoff-Khalsa, 1991; Webb & Dube, 1981). Specific states of consciousness can also be learned as adaptive behaviors to demanding circumstances (Green and Green, 1986).  
♥ I've beeen training in self-hypnosis for a while (under supervision and for a reason) and found that the 8-4 Hz beats put me very quickly in a deeply relaxed state. Definitely the thing! With the timer, I can shut them for the real self-hypnosis. I haven't tried the other beat generators yet, but this one works much better than I expected and clearly does the job. In a few words: I'm impressed!