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.

Most wisdom traditions have employed methods that allow the subjects' brain waves to slow down such as meditation, [Hindu] kirtan, [Gregorian, Menzuma or Sufi] chanting, Hebrew davening, Native American drum circles and rain chants, Tibetan prayer bowls, and whirling dervishes and African trance dancing. The rhythm of these wisdom tradition technologies actually slows people's brain waves from their normal busy brain frequency we call Beta (13-30 cycles per second or Hz), to Alpha (8-13Hz) -- meditation, Theta (4-8Hz) -- deep relaxation and dreaming, and Delta (.5-4Hz) -- slow wave or dreamless sleep.
If you search the Internet for "binaural beats" you'll quickly find there's a whole industry built on the idea that listening to binaural beats can produce all kinds of desired effects in your brain. It can alter your mood, help you follow a diet or stop smoking, get you pumped up for a competition, calm you down, put you to sleep, enhance your memory, act as an aphrodisiac, cure headaches, and even balance your chakra. offers a $30 CD that they call the world's first "digital drug". They claim it can get you drunk without the side effects. offers a range of music tracks that they say simulates a variety of actual pharmaceuticals, such as Demerol, Oxycontin, and Vicodin. Suffice it to say that no matter what superpower you're looking for, someone on the Internet sells a binaural beat audio file claimed to provide it.
Studies have shown binaural beats may affect levels of dopamine, a hormone that plays a broad role in cognition and a particular role in creative thinking. This has scientists examining the possibility that binaural beats can be used to stimulate creativity. (If you’re looking to be more creative and innovative in your thinking, keep in mind that sleep itself is a powerful tool!)
With regard to listening without headphones specifically, you might find it irritating if you are someone who suffers from motion sickness, depending on how the track is created. If you were listening to binaural beats, they really need headphones to work properly. If you are in a room and closer to one speaker you may not even hear binaural beats properly, and if sitting off centre in the room generally, that may have unsettled you if you have motion sickness as the tones try to form a beat in your head. If it was just a standard isochronic tones theta track that shouldn’t be irritating if you have motion sickness.
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.
You might not realize it, but when you’re stressed, every muscle in your body tenses up. Taking a moment to recognize this and actively relaxing each part of your body can help. According to Whitaker, common stress-storing places are the jaw, neck, shoulders, back, and stomach. “The Instant Relaxation Technique is a deliberate tightening of the entire body, starting from the toes to the head region, and letting it go instantly,” Joshi says. “This is an effective way to become self-aware of our muscles and letting go of stress very quickly.” While you do this, picture all the negative emotion and tension leaving your body. Look out for these 8 silent signs stress is actually making you sick.
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.
Dealing with sudden stress—a phone call with bad news, a last-minute assignment from your boss, or an argument with your spouse—triggers a cascade of physical and mental symptoms that can be hard to stop. The first thing to do? Pay attention to your breathing pattern, and make an effort to start taking slow, deep breaths as stress relievers. “Breathing can change how we feel because emotions and breathing are closely connected,” says Emma Seppala, PhD, author of The Happiness Track and a Stanford University psychologist who’s done research on yogic breathing. “A revealing research study showed that different emotional states are associated with distinct respiration patterns.” In a follow-up study, participants actually started to feel the emotions that corresponded to an assigned breathing pattern. “This finding is revolutionary: We can change how we feel using our breath!” Dr. Seppala says. Deep breathing gets more oxygen to your brain and may lower levels of the stress hormone cortisol.
Cortisol is an arousal hormone, stimulating alertness and attention. Cortisol levels rise and fall in connection to circadian rhythms—cortisol levels rise to their peak levels first thing in the morning, just in time for you to be active for the day. Too-high cortisol levels are associated with insomnia, as well as more time spent in light sleep, rather than deep sleep.
A person might wonder what the problem with looking for validation is; why we shouldn’t seek to compare our experiences with those others have had. Shouldn’t there be some sort of indicators that our practice is producing an effect? There are indicators, but they are not the high profile, odd phenomena most frequently looked for, and they may not become apparent immediately. Some things do take a little time.

Hey, even before we spoke about creating Journey, I was thinking about how people across the world do their spiritual practices and the commonalities between them all. I was thinking, there is the path of stillness—which links right back to what we were talking about getting to a state of deep, profound relaxation and bringing clarity into stillness. Then there’s the path of rhythm, of rocking, of dancing. But there’s always a rhythm to it—even in the movements of Tai Chi, there’s a smoothness, a smooth rhythm. What it never is, is arrhythmic—those are the movements of a more anxious, frightened animal kind of thing. 
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."  
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.

When stress attacks, it can feel like your whole world is crashing down. Remind yourself what’s good in your life with a quick gratitude round-up. “Studies show gratitude techniques like counting your blessings can be a significant stress reducer,” Dr. Serani says. “Gratitude research reports that those who utilize daily gratitude reflections have higher levels of positive emotions, life satisfaction, vitality, optimism, and lower levels of depression and stress.” Reminding yourself of the good things in life can put stress in perspective. “Studies show that cultivating an optimistic mindset can help you maintain a positive mood,” Whitaker says. “When you are positive and grateful, you are able to handle difficult situations better.” Just look out for these stress relievers that actually backfire.
Passively listening to binaural beats may not spontaneously propel you into an altered state of consciousness. One's subjective experience in response to binaural-beat stimulation may also be influenced by a number of mediating factors. For example, the willingness and ability of the listener to relax and focus attention may contribute to binaural-beat effectiveness in inducing state changes. "Ultradian rhythms in the nervous system are characterized by periodic changes in arousal and states of consciousness (Rossi, 1986).
Stress: We all deal with it, yet we know how much better off we’d be — both physically and mentally — if we could only get it under control and find stress relievers that really work. While stress can be a positive, motivating factor at times (such as when you’re under pressure to perform well at work or to ace an important exam), more and more research shows that chronic stress impacts the body in ways similar to a poor diet, lack of sleep or sedentary lifestyle.
Gamma brainwaves possess the highest frequency we know of. In this state, our brainwaves are so harmonious that many people report feeling elevated states of consciousness, even spiritual experiences. This frequency is often experienced by monks, nuns, yogis, and experienced meditators. Gamma frequencies also enhance memory, awareness, and mental processing.
Any other things help you relieve stress? “Yoga is something I always return to. I find there is something about just reconnecting to my breath and surveying my body that allows me to be very honest about how well I am managing to maintain a sense of peace regardless of the chaos around me. On a daily basis, I find cooking to be a wonderful, sensory-rich, hands-on way to unwind from a busy day.”

Research: the authors stated that qualitative electroencephalogram signatures needed to be developed for different disorders and tested using standard validated methods of psychological assessment. Larger RCTs were needed with clear inclusion criteria for participants. The RCTs should measure qualitative EEG, hormone levels and the time of day of the intervention. Interventions protocols should be clearly defined and the relationship between session frequency/ duration and outcomes should be explored. More studies of auditory stimulation were needed, as well as studies comparing different types of stimulation, monaural, binaural and isochronic beats and use of white noise versus music.

Just so, when you reach a state of meditation you don’t “keep digging”, so to speak. The hole has been dug. All that digging has done what it was meant to do. Once your technique has gotten you into meditation, STOP DIGGING! You’re there. If you keep digging you will frustrate your ability to remain in meditation for any significant period of time. Only resume your chosen technique if and when you slip out of the meditative state. If you’re human then you WILL slip out of that state again and again. Don’t worry about that. That’s how the process works for all of us mere mortals.
... Several studies have looked at the possible effects of binaural beats within the alpha range on cognitive abilities. A significant improvement in cognitive processing, as measured by the Stroop Effect exercise, was found by a BB stimulation of 10.2 Hz frequency (Cruceanu & Rotarescu, 2013).Carter and Russell (1993)exposed 8 to 12 year old boys with learning disabilities to 8-week long 10 and 18 Hz BB stimulation sessions, and they found an improvement in Raven's progressive matrices and in a subtest of auditory sequential memory (Carter & Russell, 1993).McMurray (2006)assessed the effect of 7 and 11 Hz BB on alpha brainwave activity, working memory, and attention in healthy elderly people, who are known for experiencing gradual decrease in physiological alpha activity. The 2 minutes exposure to BB resulted in an altered electrical activity in the brain. ...

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.
The most common way to use a brainwave entrainment is for a short-term benefit, to help guide your brain into a particular mental state at the time you need it.  In a similar way to how you might take a sleeping pill before bed to help you get to sleep, or maybe drink some coffee or an energy drink to help wake you up and give you a boost of energy.
The brain will entrain to the strongest stimulus. If you combine binaural beats with isochronic tones, your brainwaves will entrain to the isochronic tones. If anything, when you combine the two I believe it makes the track less effective because it makes it harder for the brain to decipher between the two and synchronise to a single beat. There are lots of websites with compelling marketing about the benefits of combining the two together in some funky way, but I haven’t seen any research or lots of anecdotal feedback even to suggest it’s effective to combine them.
No. The frequencies are consistent throughout the duration of each music production we offer. It could be argued that a better approach is to change the frequency over time, starting at a higher frequency when the listener is alert and slowly ramping down as the music progresses and the listener becomes more relaxed. So why have we not taken this approach?

The I-Doser claims it can emulate prescription drug-like effects by listening to MP3's, to get stoned.[1] This is largely a moral panic by parents who flunked science fueled by the eternal quest by teenagers to get stoned, and stupid ones convincing their friends it works. It is really more of wishful thinking and making yourself disoriented by playing discordant sounds really damn loud. If you want to experience it yourself, you can always listen to Bjork Captain Beefheart dubstep.

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.
Researchers advise that people who suffer from epilepsy or seizures should ask for professional insight first before using binaural beats. Pregnant women are also advised to seek the advice of their physicians. However, I haven’t heard anything about binaural beats impacting those who have had heart attacks negatively. That being said, I encourage you to do extra research.
Research shows that binaural beats can literally drive brain activity into specific brain states (Gamma, Beta, Alpha, Theta or Delta). Without any effort and naturally, you would have your brain activity to synchronize with the binaural beat; it will become organized and coherent, and eventually, the left and right hemispheres of your brain will start to be balanced creating a very unique state called “hemispheric synchronization” (equal frequency and amplitude of the wave forms in both hemispheres). This extraordinary brain state is very powerful and normally unattainable without this kind of stimulation. Through the entrainment of brain waves, binaural beats can influence the brain in a very subtle way, inducing states of relaxation, sleep, meditation, creativity…
Gaia Meditation Delta programs are specifically designed to: improve sleep and healing process. Effects happen at a very deep subconscious level, ideal for powerful reprogramming. If you’re in lack of sleep because you’re a busy business man or because you have insomnia etc., a few hours of our Delta waves programs will trick your brain into thinking it had all the restorative sleep it needs.
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.
Brainwave entrainment is a field of study and endeavor founded in the same physiological and psychological processes that make music, drumming, and chanting so powerful as methods for transforming the mind and spirit and aiding in healing of the body. These processes involve how the electrical energy in our brains synchronizes with sounds and visual stimuli, producing a particular brainwave frequency and its associated mental states. 
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.