Binaural Beats or Binaural Tones are auditory processing artifacts, or apparent sounds, the perception of which arises in the brain for specific physical stimuli. This effect was discovered in 1839 by Heinrich Wilhelm Dove, and earned greater public awareness in the late 20th century based on claims that binaural beats could help induce relaxation, meditation, creativity and other desirable mental states. The effect on the brainwaves depends on the difference in frequencies of each tone: for example, if 300 Hz was played in one ear and 310 in the other, then the binaural beat would have a frequency of 10 Hz. 

The brain produces a phenomenon resulting in low-frequency pulsations in the amplitude and sound localization of a perceived sound when two tones at slightly different frequencies are presented separately, one to each of a subject’s ears, using stereo headphones. A beating tone will be perceived, as if the two tones mixed naturally, out of the brain. The frequencies of the tones must be below 1,000 hertz for the beating to be noticeable. The difference between the two frequencies must be small (less than or equal to 30 Hz) for the effect to occur; otherwise, the two tones will be heard separately and no beat will be perceived. 

Binaural beats are currently being researched by Physiologists investigating the sense of hearing. 
Binaural beats reportedly influence the brain in more subtle ways through the entrainment of brainwaves and have been claimed to reduce anxiety and to provide other health benefits such as control over pain. 

Experience the auditory illusions of Binaural Beats by listening to these audio or video files with headphones on a medium to low volume, the sound should be set at a comfortable level, but not loud.  Notice how the sound waves phase each other out and create an effect of a pulsating beat. Removing one earphone will show how the Binaural Beats disappear completely. Repeat with your other ear. 

Binaural Beats Lucid Dreaming Youtube Video 

Acoustical background 

Interaural time differences 

For sound localization the human auditory system analyses interaural time differences between both ears inside small frequency ranges, called critical bands. For frequencies below 1000 to 1500 Hz interaural time differences are evaluated from interaural phase differences between both ear signals. The perceived sound is also evaluated from the analysis of both ear signals. 

If different pure tones (sinusoidal signals with different frequencies) are presented to each ear, there will be time dependent phase and time differences between both ears (see figure). The perceived sound depends on the frequency difference between both ear signals: 

If the frequency difference between the ear signals is lower than a few Hertz, the auditory system can follow the changes in the interaural time differences. As a result an auditory event is perceived, which is moving through the head. The perceived direction corresponds to the instantaneous interaural time difference. 

For slightly bigger frequency differences between the ear signals (more than 10 Hz) the auditory system can no longer follow the changes in the interaural parameters. A diffuse auditory event appears. The sound corresponds to an overlay of both ear signals, which means amplitude and loudness are changing rapidly (see figure in the chapter above). 

For frequency differences between the ear signals of above 30 Hz the cocktail party effect begins to work, and the auditory system is able to analyze the presented ear signals in terms of two different sound sources at two different locations, and two distinct signals are perceived. 

Binaural beats can also be experienced without headphones, they appear when playing two different pure tones through loudspeakers. The sound perceived is quite similar: with auditory events which move through the room, at low frequency differences, and diffuse sound at slightly bigger frequency differences. At bigger frequency differences apparent localized sound sources appear. However, it is more effective to use headphones than loudspeakers. 

History 

Heinrich Wilhelm Dove discovered binaural beats in 1839. While research about them continued after that, the subject remained something of a scientific curiosity until 134 years later, with the publishing of Gerald Oster’s article “Auditory Beats in the Brain” (Scientific American, 1973). Oster’s article identified and assembled the scattered islands of relevant research since Dove, offering fresh insight (and new laboratory findings) to research on binaural beats. 

In particular,Oster saw binaural beats as a powerful tool for cognitive and neurological research, addressing questions such as how animals locate sounds in their three-dimensional environment, and also the remarkable ability of animals to pick out and focus on specific sounds in a sea of noise (which is known as the “cocktail party effect”). 

Oster also considered binaural beats to be a potentially useful medical diagnostic tool, not merely for finding and assessing auditory impairments, but also for more general neurological conditions. (Binaural beats involve different neurological pathways than ordinary auditory processing.) For example, Oster found that a number of his subjects that could not perceive binaural beats, suffered from Parkinson’s disease. In one particular case, Oster was able to follow the subject through a week-long treatment of Parkinson’s disease; at the outset the patient could not perceive binaural beats; but by the end of the week of treatment, the patient was able to hear them. 

In corroborating an earlier study, Oster also reported gender differences in the perception of beats. Specifically, women seemed to experience two separate peaks in their ability to perceive binaural beats—peaks possibly correlating with specific points in the menstrual cycle, onset of menstruation and during the luteal phase. This data led Oster to wonder if binaural beats could be used as a tool for measuring relative levels of estrogen. 

The effects of binaural beats on consciousness were first examined by physicist Thomas Warren Campbell and electrical engineer Dennis Mennerich, who under the direction of Robert Monroe sought to reproduce a subjective impression of 4 Hz oscillation that they associated with out-of-body experience. On the strength of their findings, Monroe created the binaural-beat technology self-development industry by forming The Monroe Institute, now a charitable binaural research and education organization. 

Overview 

Binaural beats may influence functions of the brain in ways besides those related to hearing. This phenomenon is called frequency following response. The concept is that if one receives a stimulus with a frequency in the range of brain waves, the predominant brain wave frequency is said to be likely to move towards the frequency of the stimulus (a process called entrainment). In addition, binaural beats have been credibly documented to relate to both spatial perception & stereo auditory recognition, and, according to the frequency following response, activation of various sites in the brain. 

The stimulus does not have to be aural; it can also be visual or a combination of aural and visual (one such example would be Dreamachine). 
Perceived human hearing is limited to the range of frequencies from 20 Hz to 20,000 Hz, but the frequencies of human brain waves are below about 40 Hz. To account for this lack of perception, binaural beat frequencies are used. Beat frequencies of 40 Hz have been produced in the brain with binaural sound and measured experimentally. 

When the perceived beat frequency corresponds to the delta, theta, alpha, beta, or gamma range of brainwave frequencies, the brainwaves entrain to or move towards the beat frequency. For example, if a 315 Hz sine wave is played into the right ear and a 325 Hz one into the left ear, the brain is entrained towards the beat frequency 10 Hz, in the alpha range. Since alpha range is associated with relaxation, this has a relaxing effect or if in the beta range, more alertness. An experiment with binaural sound stimulation using beat frequencies in the Beta range on some participants and Delta/Theta range in other participants, found better vigilance performance and mood in those on the awake alert state of Beta range stimulation. 

Binaural beat stimulation has been used fairly extensively to induce a variety of states of consciousness, and there has been some work done in regards to the effects of these stimuli on relaxation, focus, attention, and states of consciousness. Studies have shown that with repeated training to distinguish close frequency sounds that a plastic reorganization of the brain occurs for the trained frequencies and is capable of asymmetric hemispheric balancing. 

Brain waves 
Electroencephalography 

Frequency range 
Name 
Usually associated with: 

40 Hz 
Gamma waves 
Higher mental activity, including perception, problem solving, fear, and consciousness 

13-39 Hz 
Beta waves 
Active, busy or anxious thinking and active concentration, arousal, cognition, and or paranoia 

7-13 Hz 
Alpha waves 
Relaxation (while awake), pre-sleep and pre-wake drowsiness, REM sleep, Dreams 

8-12 Hz 
Mu waves 
Sensorimotor rhythm Mu_rhythm, Sensorimotor_rhythm 

4-7 Hz 
Theta waves 
deep meditation/relaxation, NREM sleep 

< 4 Hz 
Delta waves 
Deep dreamless sleep, loss of body awareness 

(The precise boundaries between ranges vary among definitions, and there is no universally accepted standard.) 
The dominant frequency determines your current state. For example, if in someone’s brain alpha waves are dominating, they are in the alpha state (this happens when one is relaxed but awake). However, other frequencies will also be present, albeit with smaller amplitudes. 

The brain entraining is more effective if the entraining frequency is close to the user’s starting dominant frequency. Therefore, it is suggested to start with a frequency near to one’s current dominant frequency (likely to be about 20 Hz or less for a waking person), and then slowly decreasing/increasing it towards the desired frequency. 

Some people find pure sine waves unpleasant, so a pink noise or another background (e.g. natural sounds such as river noises) can also be mixed with them. In addition to that, as long as the beat is audible, increasing the volume should not necessarily improve the effectiveness, therefore using a low volume is usually suggested. One theory is to reduce the volume so low that the beating should not even be clearly audible, but this does not seem to be the case (see the next paragraph). 

Other uses 

In addition to lowering the brain frequency to relax the listener, there are other controversial, alleged uses for binaural beats. For example, that by using specific frequencies an individual can stimulate certain glands to produce desired hormones. Beta-endorphin has been modulated in studies using alpha-theta brain wave training, and dopamine with binaural beats. Among other alleged uses, there are reducing learning time and sleeping needs (theta waves are thought to improve learning, since children, who have stronger theta waves, and remain in this state for a longer period of time than adults, usually learn faster than adults; and some people find that half an hour in the theta state can reduce sleeping needs up to four hours; similar to another method of achieving a theta state, e.g. meditation;) some use them for lucid dreaming and even for attempting out-of-body experiences, astral projection, telepathy and psychokinesis. However, the role of alpha-wave activity in lucid dreaming is subject to ongoing research). 

Alpha-theta brainwave training has also been used successfully for the treatment of addictions. 
It has been used for the recovery of repressed memories, but as with other techniques this can lead to false memories. 

An uncontrolled pilot study of Delta binaural beat technology over 60 days has shown positive effect on self-reported psychologic measures, especially anxiety. There was significant decrease in trait anxiety, an increase in quality of life, and a decrease in insulin-like growth factor-1 and dopamine and has been successfully shown to decrease mild anxiety. A randomised, controlled study concluded that binaural beat audio could lessen hospital acute pre-operative anxiety. 

Another claimed effect for sound induced brain synchronization is enhanced learning ability. It was proposed in the 1970s that induced alpha brain waves enabled students to assimilate more information with greater long term retention. In more recent times has come more understanding of the role of theta brain waves in behavioural learning. The presence of theta patterns in the brain has been associated with increased receptivity for learning and decreased filtering by the left hemisphere. Based on the association between theta activity (4-7 Hz) and working memory performance, biofeedback training suggests that normal healthy individuals can learn to increase a specific component of their EEG activity, and that such enhanced activity may facilitate a working memory task and to a lesser extent focused attention. 

Quotes & Facts About Binaural Beats: 

- People suffering from cognitive functioning deficits, stress, pain, headaches & migraines, PMS and other behavioural problems all benefitted from using binaural beats. 
- “The immediate psychological effects on memory, attention, stress, pain, headaches and migraines were shown to benefit from even a single session of brainwave entrainment”. 
- One study even found that improvements in intelligence and behaviour lasted after the binaural beats were withdrawn, and that previous users could now produce the brainwave frequencies induced by BWE on their own. This suggests that the results can be permanent, even after you stop using binaural beats. 
- Binaural Beats increase relaxation, meditation, pain management, improve sleep, and reduce stress. 
- Binaural Beats help to increase creativity, relaxation and meditation. 
- Binaural Beats “increase focus, problem solving, creativity, memory, learning, sleep induction, pain control and enhanced learning”. 
- Binaural Beats “dramatically” affects the production of three hormones directly related to longevity of life and overall well-being; cortisol, DHEA and melatonin: 

Cortisol is found in the adrenal glands and impacts learning and memory, as too much of it is bad for us and causes stress. 
DHEA is used as a “source ingredient” for virtually every “good hormone” the body needs, and helps our immune system. 
Melatonin is the chemical produced during deep, natural sleep. Having lots of DHEA and melatonin is good for us. 

In a separate binaural beat research study using Holosync branded binaural beats: 

Cortisol levels went down by an average of 46% 
DHEA increased by an average of 43% 
Melatonin production increased by an average of 98%. 

-Binaural beats which take the user into the Alpha brainwave state aids production of serotonin, a hormone which increases relaxation and eases pain. 
Binaural beats which take users into the theta brainwave state help boost production of catecholamines, which are vital to memory and learning. 
-Brain wave entrainment usage has been shown to produce average IQ increases of 23%. 

In cases where the IQ was lower than 100 to begin with, the average IQ increase was 33 points.