Brainwave entrainment is a practice of administering sounds or lights for a specific duration to alter or enhance various electrical frequencies (brain waves) within the brain. Brainwave entrainment has existed for centuries, but in the early years, people didn’t really understand the science behind it. The earliest usage of brainwave entrainment was likely a result of shamanic rituals which involved the beating of drums at consistent rhythms.
The consistent rhythms produce a sound that caused humans brain waves to adapt to match or “synchronize” with the sound frequency. Although people didn’t know that their brain waves were being altered by drum beats, many noticed that they felt significantly different such as: more spiritually connected, more relaxed, and sometimes felt like they were in a trance. Generally brainwave entrainment is conducted to move the brain from a default beta wave state to a slower alpha wave or theta wave state.
This results in altered states of consciousness that may help people with stress, anxiety, depression, concentration, and creativity. Some estimate that the effects of entrainment have been documented since 200 AD when Ptolemy observed the effects of flickering sunlight from a spinning wheel. Scientific brainwave entrainment was discovered in 1934, just years after Hans Berger discovered alpha waves.
Types of Brainwave Entrainment
It is important to understand that there are two primary types of brainwave entrainment: audio entrainment – which uses sounds to manipulate brain waves, and visual entrainment – which uses light to manipulate brain waves. Most people are familiar with sound-based or auditory entrainment due to the fact that it doesn’t require special glasses or technology.
1. Auditory Entrainment
Auditory-based brainwave entrainment uses specific sound frequencies to alter or enhance various brain waves. Most people are familiar with “binaural beats,” but other formats such as monaural tones and isochronic tones tend to elicit a more potent neurological effect. Additionally the usage of music modulation can incorporate monaural tones or isocrhonic beats to entrain the brain waves.
Binaural beats require the usage of headphones to entrain the brain waves. The idea is that if you play a certain frequency in one ear (e.g. 400 Hz) and a slightly different frequency in the other ear (e.g. 410 Hz), the brain will entrain to match the difference between the two frequencies. In the event that you actually played binaural beats of 410 Hz in your right ear and 400 Hz in your left ear, the result would be entrainment at 10 Hz – a highly popularized alpha wave frequency.
Similarly if you manipulated the difference between the two beats and played one at 415 Hz and the other at 400 Hz, you’d entrain to a 15 Hz beta wave. The electrical activity in your brain would then adjust to match that specific difference between the two tones. Not all of your electrical activity would shift, but the dominant state of awareness would shift to that characterized by beta waves.
The effect of binaural beats was discovered by Heinrich Wilhelm Dove in 1839. He determined that playing slightly different frequencies in separate ears resulted in a perception of the difference between the two. In 1973, Dr. Gerald Oster noted that combining multiple tones resulted in a rhythmic beat or “binaural beat.” In order for the binaural beats to elicit an entrainment effect, the difference between the frequencies must be less than 30 Hz.
This is because when the gap between the frequencies expands beyond 30 Hz, your brain perceives them as distinct sounds, and is unable to entrain to the difference. While binaural beats can produce brainwave entrainment without headphones, this requires optimal placement of speakers (one on each side of the head). Binaural beats are thought to be perceived by a region of the brain stem called the “superior olivary nucleus.”
- Pros: Binaural beats are effective for brainwave entrainment and provide hemispheric synchronization at the brain stem.
- Cons: Binaural beats produce a weaker entrainment effect than other options, stimulate less of the cortex, and don’t work very well without headphones.
Monaural beats are similar to binaural beats in that they utilize two frequencies to create a single beat. However, they are different in that binaural beats in that two tones merge within the same speaker (or ear) rather than from two distinct sources (e.g. separate headphones). If you were to play a 520 Hz tone and 500 Hz tone through the same speaker, they would merge to create a perceived 20 Hz “monaural” beat.
Monaural beats also directly stimulate the basilar membrane, a different area of the cortex than binaural beats. The modality of brain stimulation from monaural beats is thought to result in a greater entrainment effect than that derived from binaural beats. While monaural beats haven’t been as extensively marketed as binaural beats, they are more effective for entrainment purposes.
- Pros: Monaural beats are considered more effective than binaural beats for brainwave entrainment. They provide greater degree of cortical stimulation.
- Cons: (None).
The single most effective type of auditory brainwave entrainment is conducted with the usage of isochronic tones. These tones are normal beats of a single tone or a tone that is turned “on” then “off” very quickly (i.e. pulsations). The result is a tone pulsation that entrains your brain to the specific frequency of the tone.
It is also common to combine isochronic tones with binaural beats and/or monaural beats. Whether the efficacy is increased with the combination is subject to debate. The tones are considered standard single beats. Depending on the frequency you’re entraining, it may be difficult to hear each “tone” or pulsation. Regardless of whether you can hear the tones, they are arguably the most effective format of auditory entrainment.
- Pros: Isochronic tones are the single most effective method of brainwave entrainment. An appealing aspect is that they do not require any headphones so you can listen through any speaker system. There is also some speculation that you can train each hemisphere of the brain separately by playing a specific tone in each ear.
- Cons: (None)
Another method of brainwave entrainment that many people are unfamiliar with is embedding brainwave entrainment tones within the audio of music. Some would argue that this doesn’t work as effective as other formats with pure tones, but there is some science behind it. The modulated music functions by creating virtually unnoticeable adjustments in rhythm to incorporate the entrainment tones.
With this type of entrainment, nearly any sound can be utilized for the embedding of the tones. You could pick out your favorite pop song, nature sounds, or something simple like white noise. Typically any forms of music modulation entrainment incorporate adjustments in rhythm as well and in some cases volume adjustments so that the music doesn’t overshadow the entrainment stimuli.
There is generally some distortion of audio, but with the right program, distortion is relatively insignificant. To maximize the effects of music modulation entrainment, you’ll want to make sure that you’re using monaural beats or isochronic tones rather than binaural beats as the former elicit a greater entrainment effect and do not require the usage of headphones.
- Pros: Perhaps the biggest benefit associated with music modulation entrainment is that you can listen to your favorite music while altering your brain waves.
- Cons: Music may not sound quite as good as normal due to modulation. Additionally the entrainment may not be quite as effective due to the fact that the tones are subtle.
Pitch Panning: This is another method of brainwave entrainment that involves creating binaural beats as a single sound file or tone as a “carrier.” A filter then adjusts the pitch up and down, while simultaneously panning it between each side of the stereo. This results in one side having a slightly greater pitch than the other. When a person puts on headphones, the effect of pitch panning is very similar to binaural beats. That said, you don’t need to use multiple tones to get the effect. Just one source of a sound or a file works to elicit the effect of pitch panning.
Harmonic “Box”: This is a technical term for combining multiple forms of auditory entrainment, usually monaural beats with binaural beats. There is generally a difference in the rates of the beats from the right and left side. Some believe this protocol results in faster brain waves in one hemisphere and slower waves in another. This is a concept invented by James Mann.
2. Visual Entrainment (Photic Stimulation)
While visual entrainment is less common than auditory entrainment, it is still an effective method of brainwave entrainment. Many visual forms of entrainment are classified as “photic stimulation.” Photic stimulation involves wearing glasses or goggles that flash or flicker lights at specific intervals to entrain the brain.
Photic stimulation is often combined with auditory entrainment to produce a greater degree of entrainment than either as a standalone method. A significant portion of the brain is involved in visual processing, therefore it makes sense to incorporate a visual form of entrainment if your goal is to alter or enhance certain brain waves.
Many people also use “mind machines” in attempt to target both their brain waves as well as visual field. Not only is visual brainwave entrainment effective, it may entrain the brain quicker than auditory modalities. Some have suggested that visual entrainment changes brain waves within seconds as opposed to minutes (using other methods).
- LED Glasses: Various types of LED glasses are able to generate quick pulses of light that entrain the brain. When using these glasses, you’d typically close your eyes and the bright light would penetrate the eyelid to entrain the brain. Certain types of glasses can be used with eyes open, but most were developed to be used with the eyes closed. These are commonly included with a “mind machine” but may be purchased to enhance auditory entrainment.
- Flashing Screen/Light: There are other programs that may produce subtle visual entrainment effects by creating a “flashing screen.” In other words, your computer screen is capable of flashing at a certain rate to entrain your brain waves. Some software even includes 3D visualizations that can be used with open eyes. Various visualizations at “pulsed” rates may also be effective for entraining the brain to a desired frequency. Further research is needed to verify visual pulsation formats of entrainment.
3. Electromagnetic Entrainment
Another format of brainwave entrainment occurs as a result of electromagnetic stimulation. There are various devices that use pulsations from electromagnetic fields to directly alter electrical activity in the brain. Generally this requires hooking up electrodes to the scalp at various sites and pulsating to produce specific frequencies in that particular region.
Some have argued that electromagnetic forms of stimulation may be more effective than auditory and/or visual due to the fact that brain waves are inherently electrical. There are a variety of different modalities of electromagnetic entrainment. Most professionals will make use of an EEG (electroencephalograph) to get a better understanding of how the electromagnets are entraining a person’s brain waves.
This probably isn’t a good way to entrain your brain waves if you aren’t a professional and could be problematic. Running electromagnetic currents in the wrong regions to entrain the wrong frequency of brain waves could result in detrimental effects. Therefore most people stick to the tried and true auditory or visual formats of entrainment.
What is the best type of brainwave entrainment?
If you want the most noticeable effect, you’ll probably want to utilize either isochronic tones, monaural beats, and/or a simultaneous form of visual entrainment. It really isn’t necessary to get too technical with the type of entrainment you pursue as every type is scientifically documented to work. However, there are limitations with binaural beats in regards to the area of the brain that they stimulate as well as the fact that the entrainment is generally weaker than other types.
For those who want to experience a weaker outcome with brainwave entrainment, use binaural beats and determine whether you notice anything. If you want to experience a greater effect, it is recommended to pursue isochronic tones without headphones. Isochronic tones are considered the most potent method of auditory-based entrainment.
Have you experimented with various types of brainwave entrainment? If so, feel free to share which types you’ve found most beneficial. I’ve personally used binaural beats, isochronic tones, monaural beats, and visual entrainment and have found them all effective. Isochronic tones are the most convenient and scientifically effective, but binaural beats are clearly still among the most popular.