Study after study has shown that brainwave entrainment technology is an effective way to relieve anxiety[4], and that meditation alters brainwave patterns more effectively than regular relaxation [5]. Dr. Jeffrey D. Thompson refers to the “far-reaching possibilities” to be enjoyed by using “this type of vibrational technology” to encourage healing, emotional release, stress reduction, relaxation and, of course, deeper meditation [6].
The same can be applied to the auditory senses, instead of the visual. Think of when you walk around the city with a friend or relative, have you ever noticed that your steps end up synchronized? Or when you walk with music which just happens to have a walkable tempo, before you know it you’re walking to the beat! This is how some insomniacs get treated. Binaural beats or brainwave entrainment aims to naturally help you synchronize yourself to a desired state of mind.

Another uncontrolled study asked eight adults to listen to a binaural beat CD with delta (1 to 4 Hz) beat frequencies for 60 days straight. The participants filled out surveys before and after the 60-day period that asked questions about their mood and quality of life. The results of the study found that listening to binaural beats for 60 days significantly reduced anxiety and increased the overall quality of life of these participants. Since the study was small, uncontrolled, and relied on patient surveys to collect data, larger studies will be needed to confirm these effects.
Despite the vast differences between each individual, our brain’s inner workings are remarkably similar. Brainwave Entrainment was built around these fundamental similarities and has equally powerful effects for almost everyone who uses it. While each situation may require a different frequency or audio track, Brainwave Love has one of the most complete, effective libraries to cover your every need. Take a look now:
Beware simple answers to complex problems, or easy methods for accomplishing difficult goals. If you combine this maxim with the advice to be skeptical of any claims that are being made in order to sell you something – then ironically you have a simple method (perhaps I should call it an “elegant” method) for protecting yourself from most scams and cons. Actually the application of this combination of maxims can be complex, but what it does do is trigger doubt and skeptical analysis. (And to be clear I am not saying that all simple solutions must be wrong – you should just beware them, meaning your skeptical senses should be tingling.)

The research may represent the bravest frontier of brain research. But depending on your religious beliefs, it may also be the last straw. For while Newberg and other scientists say they are trying to bridge the gap between science and religion, many believers are offended by the notion that God is a creation of the human brain, rather than the other way around. "It reinforces atheistic assumptions and makes religion appear useless," said Nancey Murphy, a professor of Christian philosophy at Fuller Theological Seminary in Pasadena, Calif. "If you can explain religious experience purely as a brain phenomenon, you don't need the assumption of the existence of God."
You won’t recall ever being in this state, but it’s an incredibly important brainwave for your health. In this state, you will be deeply asleep, but not actively dreaming. Your body needs this state to heal and regenerate. On a daily basis, you’ll need to achieve this state when you sleep at night to make sure your body can heal itself. When you’re feeling really sick or your body and mind are working hard, you’ll want to stay in this state a little longer.
Binaural-beat perception originates in the inferior colliculus of the midbrain and the superior olivary complex of the brainstem, where auditory signals from each ear are integrated and precipitate electrical impulses along neural pathways through the reticular formation up the midbrain to the thalamus, auditory cortex, and other cortical regions.[6]

Brainwave entrainment through audio can be triggered through a variety of techniques, including binaural beats, isochronic tones, monaural beats, and modified audio tracks. The brainwavetones are embedded into the audio and the listener is unaware of their presence. He or she simply enjoys the audio track as a pleasurable listening experience, while the various tones generate frequencies in a way that encourages the brainwaves to respond and “get in step.”

Transparent Corp's Research Area is arguably the most comprehensive resource for collated brainwave entrainment research.   Update: the main research area on Transparent Corp's website is currently being updated, so it is offline.  However, you can still access their peer-reviewed research paper as a PDF here: “A Comprehensive Review of the Psychological Effects of Brainwave Entrainment“.
^ Jump up to: a b Fox, Kieran C.R.; Nijeboer, Savannah; Dixon, Matthew L.; Floman, James L.; Ellamil, Melissa; Rumak, Samuel P.; Sedlmeier, Peter; Christoff, Kalina (2014). "Is meditation associated with altered brain structure? A systematic review and meta-analysis of morphometric neuroimaging in meditation practitioners". Neuroscience & Biobehavioral Reviews. 43: 48–73. doi:10.1016/j.neubiorev.2014.03.016. PMID 24705269.
Founder and president of Brain Sync, Kelly Howell is internationally acclaimed for her pioneering work in mind expansion. The author of over 60 best-selling audio programs, Kelly is the creator of Brain Sync's Brain Wave Audio Technology. "Kelly Howell is a masterful guide in helping to integrate body, mind, and spirit. In an age where life is becoming increasingly hectic, her instruction is invaluable." Larry Dossey, MD Author: THE EXTRAORDINARY HEALING POWER OF ORDINARY THINGS Eminent scientists and medical professionals such as Harvard-trained neurosurgeon Norman Shealy, MD, PhD have used programs developed by Kelly in their professional practices. Her 20 years of research into spiritual practices and meditation, combined with her work with physicians and biofeedback therapists, have enabled Brain Sync to refine its extraordinary audio technology into the exceptionally powerful, life-enhancing audio programs so many have come to rely on.
The pitch frequency measures and describes what a beat sounds like, i.e. does the isochronic beat have a deeper bass sound, or is it high pitched and sharper sounding? The beat waveform frequency describes how many times the beat is repeating per second, i.e. how fast it is beating. You don’t really need to concern yourself about the pitch frequency, as that doesn’t have a direct influence on brainwave entrainment and doesn’t play a part on the measurement on an EEG. I only mentioned it because you were referring to humans not being able to hear below 20Hz. I change the pitch frequency just to suit the mood of the track. For tracks that are to be relaxing, for meditation or sleep, I tend to use a lower pitch frequency so it sounds deeper and more relaxing and I never have that lower than 100Hz. For an energizing, high focus track I might use a more higher pitched 200Hz isochronic tone, because that is sharper sounding and less likely to make you feel sleepy. That’s all you really need to know about the pitch frequency.

The name of the game (and by game, we mean mind hack) is binaural beats. Binaural beats refer to the event in which two similar — but not identical — frequencies are played in different ears through headphones. For example, you might have a 300 Hz tone playing into your left ear, and a 305 Hz tone playing into your right ear (hence the need for headphones, since it’s important for the different sounds to be heard in isolation). Your brain will hear those two tones, yes, but what it will also pick up a 5 Hz tone – the difference between the two frequencies – which is actually too low for our ears to hear. So what’s happening here is not that your ears are suddenly picking up a tone that they couldn’t prior, but instead, your brain is producing the tone; you are perceiving it, not actually hearing it. The resulting noise that you will hear is a steady rhythm, about 4.5 beats per second. Your brain, in the process, will actually emit brainwaves at the frequency of the synthesized tone.
The following is an example of binaural beats incorporated into an actual piece of music and had even made the headlines as “the most relaxing song ever”. The song is called “Weightless” and is composed by the band Marconi Union, reportedly in collaboration with sound therapists. The official explanation is that the track would start on 60 beats per minute and slowly but surely slow it down to 50.
Other entrainment methods sometimes used include autopan modulation that moves sound in an 180º arc to create a desired tone. Harmonic box entrainment, invented by James Mann, uses a layering of binaural and monaural tones that alternate between ears, requiring headphones. Sound modulation and filtering, amplitude modulation, and pitch panning use diverse sounds to create rhythmic pulses matched to the desired brainwave frequency. 
I am one of the fortunate ones who received a free demo of your product. I do believe your product corrected damage to my brain from a childhood concussion. Immediately upon use, I became aware of sounds, drainage and even discomfort behind my right eye and the lower right side of my skull. This continued for a week of using the product daily. I was about to give up using the product when all discomfort stopped, and has not returned. I do believe your product should be used for childhood head trauma. Even though the brain is only bruised, a life can be altered immensely. I love my Equisync II and will use it daily and with confidence.
Binaural beats are created from two different continuous tones, which when sent separately to each ear create a single beat inside your head. Isochronic tones are basically a single tone which is switched on and off at regular intervals. Imagine a single continuous tone playing on a stereo system and you’ve got your hand on the volume switch. Then once per second, you turn the volume off for half a second and keep doing that every second. For half a second the volume is off, for the other half a beat waveform is formed. The beat is cycling once per second per second, i.e. at a rate of 1Hz.
While visual entrainment is more powerful than audio alone for inducing desired brainwave states, more caution is needed when using visual methods. Between 0.3 and 3 percent of the population is susceptible to having seizures from flickering light stimulation, and for other people, flickering visual stimuli simply makes them uncomfortable. People with epilepsy have a greater chance of having a seizure from exposure to flickering light stimulation.
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:
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...
Since opening their online store in 2011, Binaural Beats Meditation has served “hundreds of thousands” of customers, according to James Matthews, the site’s customer happiness manager. “We continue to see an increase in interest… from individuals, but increasingly so from therapists using the music to help clients, health and wellness organizations, and businesses around the world.”
With these studies in mind, EquiSync's revolutionary, multi-layered, multi-tiered approach was born. Designed to synchronize and harmonize your brainwaves while allowing you access to the deepest, most pleasurable, most beneficial states of meditation — much faster than the traditional route, EquiSync® has made mastering meditation easier than ever!

Long-term meditation practitioners have also shown to have a higher tolerance for pain.[15] This effect has been correlated to altered function and structure in somatosensory cortices and an increased ability to decouple regions in the brain associated with the cognitive appraisal of pain (anterior cingulate cortex and dorsolateral prefrontal cortex).[16]
Participants were experienced practitioners of Acem Meditation, a nondirective method developed in Norway. They were asked to rest, eyes closed, for 20 minutes, and to meditate for another 20 minutes, in random order. The abundance and location of slow to fast electrical brain waves (delta, theta, alpha, beta) provide a good indication of brain activity.
Hi Marko, that isn’t one of my videos you referred to, so I can’t really answer you properly as I don’t know how their track was created. For the best answer, you should really contact the video creator. There isn’t any research that I’ve seen to suggest that you could harm your health by looping a delta track. During a typical sleep cycle, your brainwave activity will usually go up and down between the delta and theta range. It may be that you won’t experience the same quality of sleep if you spend most of your time producing mainly delta activity. With my 8-hour sleep track, I fluctuate the frequency range to try and emulate a typical sleep cycle

But we don't need any studies to tell us that different people can listen to different kinds of music and be affected. A lot of people who work out have a workout playlist on their iPod that keeps them energized. Some people listen to certain music to help them fall asleep. The Muzak company has built an industry on relaxing music that will keep people in the mood to shop. Music does affect our mood, and so we already have every reason to expect binaural beat recordings to produce the same effect. Different people may find certain binaural beats to be relaxing or energizing. But, we've never found any reliable indication that a binaural beat's connection to our brain is any deeper or more meaningful than any other music track. We do know for a reasonable certainty that specific claims made by most sellers of binaural beats are not credible, and that there is no reason to think that the effect they're claimed to produce will work for you.