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. 
How does brainwave entrainment work? Consistent, precisely engineered audio frequencies in the form of binaural beats cause the brain’s frequencies to match the stimulus. Your brain perceives two beats with slightly different frequencies (which are inaudible to the ear) through your headphones. It takes the difference between the two, and matches its own frequency to it. This is called the “frequency following” response.
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.

In the 1980s, a researcher in Japan, Tsuyoshi Inouye described how light stimulation creates synchronization of brain hemispheres. Since then, other researchers have detailed the positive effects of hemispheric synchronization including a 1984 study by researcher Dr. Gene W. Brockopp stating that hemispheric synchronization resulted in improved intellectual functioning as well as improvements in long-term memory, and these effects are cumulative over time.

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.
This is not to say that entrainment cannot produce some physical effects, particularly negative ones. It is possible to induce epileptic seizures using entrainment, especially visual entrainment that employs flashing lights. That’s why people with seizure disorders are uniformly told to consult with their health care provider before using entrainment if they have a seizure disorder or some other serious medical condition.
The binaural-beat appears to be associated with an electroencephalographic (EEG) frequency-following response in the brain (3). Many studies have demonstrated the presence of a frequency-following response to auditory stimuli, recorded at the vertex of the human brain (top of the head). This EEG activity was termed "frequency-following response" because its period corresponds to the fundamental frequency of the stimulus (Smith, Marsh, & Brown, 1975). Binaural-beat stimulation appears to encourage access to altered states of consciousness.
Writing or talking about the things that prey on you—in a diary, with friends, in a support group or even a home computer file—helps you feel less alone and helpless. One study, published in The Journal of the American Medical Association, looked at people who had either rheumatoid arthritis or asthma— conditions known to be stress-sensitive. One group chronicled in a perfunctory manner the things they did each day. The other group was asked to write daily about what it was like, including fears and pain, to have their disease. What researchers found: People who wrote at length about their feelings had far fewer episodes of their illness.
I have purchased the two meditations I mentioned which are theta and 7 chakra frequencies. I tend to be a bit hesitant to register and/or buy from sites I don’t know, that’s why I asked you. But I got over my trust issues and already wrote the creator. He is most helpful. In case someone is wondering: the ‘higher spiritual awareness’ refers to a deeply meditative experience.
Stress levels and a proper diet are closely related. When we’re overwhelmed, we often forget to eat well and resort to using sugary, fatty snack foods as a pick-me-up. Try to avoid sugary snacks and plan ahead. Fruits and vegetables are always good, and fish with high levels of omega-3 fatty acids have been shown to reduce the symptoms of stress. A tuna sandwich really is brain food.
The body responds in essentially the same way to made-up imagery as it does to real experiences. Positive, relaxing images can be an effective tool for relieving stress. Try it for yourself with this Guided Imagery podcast from our Founder and Director Dr. James Gordon, or check out Dr. Gordon’s book Unstuck: Your Guide to the Seven-Stage Journey Out of Depression for dozens more techniques, including scripts for guided imagery exercises.
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.
♥ When I learned about Binaural beats and found out how you can influence your state of mind, I utilized them for most of my college studies. I play 16Hz Beta waves behind my favorite study music. I've been using them for 3 years now and they help me stay focused longer. Just make sure you have quality headphones that can reproduce the frequencies accurately. 2Hz does make a difference with an EQ.
Because the mind and body are a single system, changing our brainwaves and spending more time in harmonious, relaxed, and restorative mind-states also affects our physical health. Physical health then reinforces our mental-state, and a feedback loop of either positive or negative processes becomes established. Research studies have shown beneficial effects of using brainwave entrainment for treating migraine headaches, premenstrual syndrome, and for managing physical pain.
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.
The Transparent Corp forum – This forum is an invaluable resource for any brainwave entrainment user or enthusiast.  Most of the feedback is obviously focused on the Transparent Corp software, but with over 20,000+ posts now you can find answers to the whole array of brainwave entrainment questions on there.  (UPDATE: Sadly, the Transparent Corp forum has now been taken offline)
♥ I've suffered from patches of insomnia throughout my life, extending from a few days to dragging on for several weeks, and no amount of the usual proper "bedtime ritual" normally recommended, calms me, as my brain is overactive. Layering combos of the Binaural/Bilateral sounds right before sleep effectively resets me, allowing me to sleep like a normal human. I can't express enough gratitude!
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 research investigates the brainwave entrainment process and aims to demonstrate the usefulness of such an approach within the framework of cognitive performance improvements. In the introductory part the theories regarding the neurophysiological structure and the psychological processing of the cognitive system are discussed, for each of their components that are considered to be relevant for this research. The hypothesis states that the stimulation with binaural beats and stroboscopic light, synchronized at 10.2 Hz frequency, will produce a positive change in cognition. The research variables are the cognitive performance (the dependent variable) and the brainwave entrainment (the independent variable). The brainwave entrainment program consists in the synchronized application of Alpha binaural beats and stroboscopic light, at a 10.2 Hz frequency, in a 30 minutes long session. The difference was made by the stroop effect based exercise that was used as a frame. There were 60 participants, divided into two independent samples. The two independent samples t test for the means differences was used in the statistical analysis. The obtained results by evaluations and by statistics confirmed this research's hypothesis, stating that the stimulation with binaural beats and stroboscopic light, synchronized at 10.2 Hz frequency, will produce a positive change in cognition.
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“.

Because of the way they are created, there may be a positive benefit from listening to binaural beats without considering the brainwave entrainment aspect, but I haven’t seen any research on that. I first discovered brainwave entrainment through binaural beats about 10 years ago now, but they didn’t do anything for me. So I’ve never been a regular user of them. I believe isochronic tones are a more effective way to produce hemispheric synchronisation because they produce a much stronger response in the brain
Entrainment is a phenomenon by which some external sensory stimulation synchronizes brainwaves differently than the native rhythm. The most obvious example of this is photic driving – during an EEG the subject will have a strobe light flashed before them at various frequencies. The purpose of this is to see if it will trigger seizure activity. In many normal subjects the brain wave rhythm in the occipital lobes, which is the visual part of the cortex, will match its frequency to the frequency of the strobe light. This specifically is called photic driving, but the phenomenon in general is called entrainment.

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:

Hi Ulka, thanks for your compliment on my article. Unfortunately, I haven’t come across any studies or much discussion about the problem with habituation and isochronic tones and how to overcome it. The consensus among experienced users is to regularly change the frequencies and music soundtracks you listen to. Adding music to the tones does change the waveform you are stimulated with, so that’s one of the main reasons why I provide different soundtracks for my isochronic tones sessions. I have released some tracks which use amplitude modulations in the music, instead of isochronic tones. It might be worth giving them a try if you haven’t already. I have them in a playlist on YouTube https://www.youtube.com/watch?v=Lj5tHl2cuWw&list=PLveg0IEcZWN6OIRZyLkv0BJADY7Q6xFCl.
Alpha: Alpha brainwave patterns are associated with a state of wakeful relaxation. Slower and lower in frequency (between 9-14 hertz), alpha waves are dominant when we’re calm and relaxed, but still alert. Alpha waves are associated with states of meditation (your yoga class probably puts you in an alpha state), and also with our ability to be creative.
When people begin to believe these kinds of claims it is only half a step further for them to begin to attribute all of their own curious little experiences to entrainment. After all, they reason in the back of their minds, if 3.84Hz can cure an ovarian cyst, isn’t it just as reasonable that listening to a track at 8Hz might cause the room to appear to spin and change colors? There is an old saying that suggests that the more outrageous a claim is, the more people will be inclined to believe it. Don’t fall for outrageous, ridiculous claims. If you do you’re heading for disappointment, guaranteed.
When delta waves are present, our awareness of the external world decreases and shuts off. People with ADD have problems with delta waves occurring when they are trying to focus, and focus and attention become increasingly impossible with stronger delta waves. Studies show a reduction of anxiety, improvements in insomnia, and elimination of headaches when people engage in sessions of delta brainwave entrainment.
Stress levels and a proper diet are closely related. When we’re overwhelmed, we often forget to eat well and resort to using sugary, fatty snack foods as a pick-me-up. Try to avoid sugary snacks and plan ahead. Fruits and vegetables are always good, and fish with high levels of omega-3 fatty acids have been shown to reduce the symptoms of stress. A tuna sandwich really is brain food.
Isochronic tones work just the same in delta as they do in alpha, theta and beta and they are widely used in the brainwave entrainment community to help people sleep. Like you, I’ve also seen some websites saying they don’t work in delta, but it’s a bit like the game of Chinese Whispers, where someone makes a comment and then after it gets passed around and shared a lot the message gets distorted and appears to be a fact. I don’t know of any scientific reason why they wouldn’t work in delta. I remember some people talking about this on a brainwave entrainment forum many years ago. They were saying they found isochronic tones a bit too abrupt for using to help them sleep and they preferred binaural beats, as they thought they were a more soothing sound. That was just a personal preference shared by a couple of prominent forum members at the time and some people then took that as a fact for everyone. That’s where I think that belief originated from.
“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.”
The studies included in the recent reviews of Tai Chi and yoga indicate that sessions between 60 and 90 minutes performed 2 to 3 days per week were effective in reducing stress and improving feelings of well-being (7,14,17). A study conducted in a worksite environment showed that 15 minutes of chair-based yoga postures was effective in reducing acute stress when assessed by self-report and with physiological measures (e.g., respiration rate and heart rate variability parameters). This finding indicates that shorter duration sessions can be effective in reducing acute stress with this type of exercise (15).
Most programs start at a work/life busy brain Beta frequency of twenty light flashes per second (20Hz) and slowly ramp them down to Alpha (relaxation and meditation) at 8-12 HZ, Theta (deep relaxation and dreaming) at 4-8 Hz) and Delta (dreamless deep relaxation) of .5-4Hz. We have taken measurements at Mass General with state of the art EEG equipment and have seen a slowing of the brain waves from Beta to Theta in two minutes and complete brain wave harmonization in the left, right, anterior, posterior and occipital regions of the brain.

Entrainment is like priming the pump of meditation. It doesn’t “cause” meditation any more than pouring that little bit of water into the pump initially “causes” water to appear in the well. The water was already there. The conditions for the pump to do its job just needed to be set up. What entrainment does is to create the conditions and the internal environment typically associated with meditation. You could get to that point without entrainment, certainly, but the entrainment allows you to get there quicker, more consistently, and to remain there for longer periods of time than you would ordinarily be capable of doing on your own.
♥ I've suffered from patches of insomnia throughout my life, extending from a few days to dragging on for several weeks, and no amount of the usual proper "bedtime ritual" normally recommended, calms me, as my brain is overactive. Layering combos of the Binaural/Bilateral sounds right before sleep effectively resets me, allowing me to sleep like a normal human. I can't express enough gratitude!
Progressive muscle relaxation is a two-step process in which you systematically tense and relax different muscle groups in the body. With regular practice, it gives you an intimate familiarity with what tension €”as well as complete relaxation €”feels like in different parts of the body. This can help you react to the first signs of the muscular tension that accompanies stress. And as your body relaxes, so will your mind.

Tracks that move from alpha to theta can be a perfect vehicle for transitioning from a hectic day into a relaxing and rejuvenating sleep. Beginning with alpha waves takes you into a light but still alert meditative mind state where the difficulties of the day can be resolved and put to rest. Later, theta waves go deeper into the unconscious, preparing you for sleep and dreams.
However, yoga and meditation take time to learn and master, and until the student becomes proficient, progress can be slow and frustrating, leading many people to abandon the effort before they see the benefits. Brainwave entrainment has the potential for helping a person enter the relaxing and rejuvenating mind-states brought about by yoga and meditation without the learning curve and time needed for mastering these other techniques. Brainwave entrainment may even facilitate learning other mindfulness methods by helping a person achieve success faster and more reliably. 
That is generally where the science ends and the pseudoscience begins. A number of companies and individuals have then extrapolated from the phenomenon of entrainment to claim that altering the brain waves changes the actual functioning of the brain. There is no theoretical or empirical basis for this, however. Entrainment is a temporary effect on the synchronization of neuronal firing – it does not improve or increase brain functioning, it does not change the hardwiring, nor does it cure any neurological disorder. There is no compelling evidence for any effect beyond the period of entrainment itself.
Another very useful application for the Theta & Delta frequencies is to keep your eyes open while listening to the entrainment recordings. Simply pick a spot on the wall and look beyond it as if you were looking at the view beyond the wall. Keeping your eyes open while in Theta and Delta brainwave states stimulates connections between the visual information processing centers of your brain and the "dream vision" centers that normally only function with the eyes closed.

Theta waves are associated with ➤ Increased sense of inner peace and emotional stability ➤ Deep relaxation ➤ Improved memory ➤ Heightened intuition and inspiration ➤ Calms the chatter of your mind ➤ Increased psychic abilities and sense of spiritual connection ➤ Speed healing, improved physical healing ➤ More restful sleep ➤ Release beneficial hormones related to health and longevity ➤ Reduce mental fatigue ➤ Reduction of anxiety and stress

Why is exposure to these soundwaves helpful to sleep and relaxation? Science shows that exposure to binaural beats can create changes in the brain’s degree of arousal. Listening to these sounds that create a low-frequency tone, research indicates, triggers a slow-down to brainwave activity—and that may help you relax, lower your anxiety, and can make it easier for you to fall asleep and sleep more soundly.
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.
You don't have to buy one, though. It's not too hard to make your own binaural beat, and free software is widely available to do just that. The one that I used to make that little sample is an open-source program called Gnaural, available on the Sourceforge website. It's pretty easy to use, though it takes some practice before you can generate some of the really cool, more professional sounding beats. A binaural beat consists of two simple tones, and most people add that background pink noise. Nothing special.
This simple app doesn’t have tons of bells and whistles, but by being just a one-screen app it doesn’t drain your battery or interfere with other apps you might be running. The interface is straightforward and lets you input exactly what binaural beats frequency you want to achieve. This is a great app if you know exactly what you want and you don’t want anything to get in the way of that.

Our brainwave states are natural. Guiding the brain into those states intentionally by using entrainment is just another way of experiencing those same natural states. Nothing “unnatural” is produced by the brain as a result of using entrainment. The only thing that is different is that when using entrainment we often go into the experience with either general expectations, or a well defined laundry list of specific expectations that we associate with entrainment. We have no such list going throughout our normal day when we’re not using entrainment.
The authors concluded that preliminary evidence suggested that brainwave entrapment was an effective therapeutic tool, but further research was required. The evidence presented appeared to justify the recommendation for further research. In view of the lack of controlled evidence and problems with methodology and reporting in the review, the authors’ conclusions regarding efficacy did not appear reliable.