Beating can also be heard between notes that are near to, but not exactly, a harmonic interval, due to some harmonic of the first note beating with a harmonic of the second note. For example, in the case of perfect fifth, the third harmonic (i.e. second overtone) of the bass note beats with the second harmonic (first overtone) of the other note. As well as with out-of tune notes, this can also happen with some correctly tuned equal temperament intervals, because of the differences between them and the corresponding just intonation intervals: see Harmonic series (music)#Harmonics and tuning.


♥ 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!
The Alpha state is an intensely pleasurable and relaxed state of consciousness, essential for stress reduction. Alpha is associated with deep physical and mental relaxation, but not quite meditation. Alpha waves instill a sense of mild euphoria, calm your body, reduce Cortisol levels, strengthen your immune system and counteract the negative effects of stress. Alpha waves also increase the production of Melatonin to greatly improve the quality of your sleep.
A therapy that slows brainwave activity, helping to produce low frequency waves, is likely to aid relaxation and sleep. But it’s not only lowering brainwave frequency that binaural beats may offer to sleep and relaxation. A small study (19 people) has found that exposure to binaural beats is associated with changes to three hormones important to sleep and well being:

The brain state changes found in meditators are almost exclusively found in higher-order executive and association cortices.[13] This supports the notion that meditation increases self-regulation and attentiveness. Recent studies have also investigated how these changes may alter the functionality and connectivity of the default mode network, which is a hypothesized network of brain regions that are active when an individual is engaged in internal tasks such as daydreaming.[17]
3. Alpha State: (9 — 13Hz) Brain waves start to slow down out of thinking mind. We feel more calm, peaceful and grounded. We often find ourselves in an “alpha state” after a yoga class, a walk in the woods, a pleasurable sexual encounter or during any activity that helps relax the body and mind. We are lucid, reflective, have a slightly diffused awareness. The hemispheres of the brain are more balanced (neural integration).

If brainwave entrainment leaves you with unwanted side-effects (see below) or discomfort, you’re probably encouraging a range of brainwaves that are already excessive in some area of your brain. The way around this is to get a brain map to see what your brain’s strengths and weaknesses are, and see what (if any) brainwaves could use some encouragement. 
(Shannahoff-Khalsa, 1991; Webb & Dube, 1981). These naturally occurring shifts may underlie the anecdotal reports of fluctuations in the effectiveness of binaural beats. External factors are also thought to play roles in mediating the effects of binaural beats (Owens & Atwater, 1995). The perception of a binaural beat is, for example, said to be heightened by the addition of white noise to the carrier signal (Oster, 1973), so white noise is often used as background. "Music, relaxation exercises, guided imagery, and verbal suggestion have all been used to enhance the state-changing effects of the binaural beat" (Owens & Atwater, 1995). Other practices such as humming, toning, breathing exercises, autogenic training, and/or biofeedback can also be used to interrupt the homeostasis of resistant subjects (Tart, 1975).

A person driving on a freeway, who discovers that they can't recall the last five miles, is often in a theta state - induced by the process of freeway driving. This can also occur in the shower or tub or even while shaving or brushing your hair. It is a state where tasks become so automatic that you can mentally disengage from them. The ideation that can take place during the theta state is often free flow and occurs without censorship or guilt. It is typically a very positive mental state.
Theta brainwaves are next highest in frequency above delta and are especially important for many people using brainwave entrainment and meditation because theta waves are at a threshold, forming a link between wakefulness and the subconscious mind. Theta waves bridge between our awake self and the creative and insightful understandings from below our conscious awareness, and while they are not common in awake adults, they are normative for children under 13 years old. 
Theta: This brainwave pattern is associated with deep relaxation and with some stages of sleep, including the lighter stages of non-REM (NREM) sleep. REM sleep itself is mostly composed of beta wave and other activity that’s similar to an alert, waking brain. Deep meditation produces theta waves, which are slower and lower frequency (between 5-8 hertz) than Alpha waves. That murky barrier between sleep and wakefulness, when you’re drifting in and out of sleep, and your thoughts feel dreamlike and difficult to remember? That’s a theta-dominant state of consciousness.
According to the Wikipedia entry “(i)n acoustics a beat is an interference pattern between two sounds of slightly different frequencies, perceived as a periodic variation in volume whose rate is the difference of the two frequencies.” Further, a binaural beat is “… an auditory illusion perceived when two different pure-tone sine waves, both with frequencies lower than 1500 Hz, with less than a 40 Hz difference between them, are presented to a listener dichotically (one through each ear)”. If the two frequencies are, say, 5 Hz apart as in 500 and 505 Hz, then a third tone at 5 Hz will be heard in addition to the two pure tones. What this technique allows for is the creation of an apparent auditory signal that can be perceived and that is at a predictable frequency. In this way, relatively low frequencies can be generated that can be easily perceived and that can correspond to the common brainwave frequency bands. These are often categorized as delta (0.5 – 4 Hz), theta (4 – 7 Hz), alpha (8 – 12 Hz), and beta (13 – 16 Hz). You may find somewhat different ranges and bands other than these listed depending on the source you consult. It is also possible to produce flashes of light that can be administered within these frequency bands but there is some risk of inducing seizures in susceptible individuals. While the most common frequency range for inducing seizures is 15 – 25 Hz, unfortunately, the possible range is 1 – 65 Hz, which covers essentially the whole range of standard EEG frequency bands. This makes use of sound stimulation safer than visual or combined audio/visual stimulation. 
Also, don’t you think that the inherent hemispheric synchronization using binaural beats might be a positive benefit within itself? While it’s true that the huge majority of us use both sides of our brains most of the time, it’s also true that many of us are a bit polarized to one side or the other in general, or when doing a particular kind of activity or focus. I’ve found stimulating a more equally and consistently whole brain activity has it’s own benefits other than the entrainment aspect.

Neural oscillations are rhythmic or repetitive electrochemical activity in the brain and central nervous system. Such oscillations can be characterized by their frequency, amplitude and phase. Neural tissue can generate oscillatory activity driven by mechanisms within individual neurons, as well as by interactions between them. They may also adjust frequency to synchronize with the periodic vibration of external acoustic or visual stimuli.[3]
One can also learn to control and slow down their brain waves through various neurofeedback technologies such as electroencephalograph (EEG), galvanic skin response (GSR), and heart, pulse and breath rate monitors. These devices measure stress and relaxation parameters and then "play" back the signals to the user so they can use the signals as a beacon to guide and "steer" themselves into a relaxed state. This takes some time, work and discipline but is much quicker than learning meditation.
Hi i’m just writing to let you all know that your Equisync CD’s are amazing! Just last night i was meditating to “Equisync II”. The one that has mostly theta binaural beats in it. I gotta tell you i have never had a meditation like i experienced with this CD. At certain points during the meditation it felt like my whole damn body was vibrating! That very night when i went to sleep I also had lucid dreams! It was so relaxing! I’ve tried “Equisync I” too, that one is amazing as well! I haven’t tried “Equisync III” yet. I can only imagine what that is going to be like!
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.
If you name your emotions, you can tame them, according to new research that suggests why meditation works. Brain scans show that putting negative emotions into words calms the brain's emotion center. That could explain meditationÕs purported emotional benefits, because people who meditate often label their negative emotions in an effort to let them go.
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.
I received my order on Mon. and have done 3 or 4 sessions of Equisync I. I just wanted to say I can already notice a difference in myself. I am much calmer and more clear thinking already in just 2 days. I don’t think it’s my mind playing tricks on me. Is this a common occurrence? Your product is great I can’t wait to try Equisync II and Equisync III.

(Shannahoff-Khalsa, 1991; Webb & Dube, 1981). These naturally occurring shifts may underlie the anecdotal reports of fluctuations in the effectiveness of binaural beats. External factors are also thought to play roles in mediating the effects of binaural beats (Owens & Atwater, 1995). The perception of a binaural beat is, for example, said to be heightened by the addition of white noise to the carrier signal (Oster, 1973), so white noise is often used as background. "Music, relaxation exercises, guided imagery, and verbal suggestion have all been used to enhance the state-changing effects of the binaural beat" (Owens & Atwater, 1995). Other practices such as humming, toning, breathing exercises, autogenic training, and/or biofeedback can also be used to interrupt the homeostasis of resistant subjects (Tart, 1975).


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.
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