Human Brain States of Meditation

Brainwave Entrainment Technology

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Auditory Applications for Theatrical Use

Brainwave entrainment technology has become well known commercial tool in the field of self-help, but the use of its effects pertaining to a live theatre audience have remained largely unexplored.  This article will examine the history of brainwave entrainment technology to determine how the technology can be used as a powerful tool in a sound designer’s arsenal.  Specific emphasis will be placed on how forms of auditory brainwave entrainment can be used in conventional live theatrical environments to entrain members of the audience.

The human brain is composed of billions of cells.  The interaction of these cells through the process of thought produces electrical energy that results in a measurable cyclical pattern known as a brainwave.  The frequency of brainwaves change depending on the level of brain activity required to perform various tasks.  There are four levels (or states) of categorization used to analyze human brainwave activity.

Beta Waves (13 – 30Hz)

Beta brainwave activity is associated with normal daily activity and consciousness.  Mental processes such as logic, reasoning and critical thinking all take place in the Beta state.  They are the highest in frequency and the lowest in amplitude.  These brainwave patterns are also the least synchronous waveforms of the four states. This is characteristic due to the complex combination of cognitive, sensory, and motor functions we perform simultaneously within this range of brainwave activity.  We are not born with the ability to produce Beta waves frequencies.  Researchers discovered that young children spend the majority of their waking hours in an Alpha state, not Beta.  This is likely because they have not yet developed the neurological pathways required for handling the complex cognitive tasks of adult life.

Beta waves have several uses pertaining to a live theatrical audience.  Because it may take several minutes for an audience member to sync to an auditory beat, preshow provides ample time for the sound designer to begin the entrainment process.  Most audience members will enter the space and begin analyzing the preshow set and lighting to deduce the experience in which they are about to partake.  This allows a sound designer to establish an entrainment technique within the preshow effects that will entrain the audience members (from varying frequencies of the Beta range) to a Beta wavelength of his choosing.  Because we are all used to the Beta state in our waking hours as adults, beginning entrainment in this manner would not likely to cause discomfort.  Higher frequency Beta waves (above 32 hertz) tend to cause feelings of restlessness or anxiety.  This can be a useful frequency to entrain to in a theatrical moment where this feeling would be deemed appropriate.

Alpha Waves (8 – 12 Hz)

Alpha brainwave activity is associated with a more restful state, but still of the wake mind, and it is generally believed to have several healing properties for stress, insomnia and attention deficit disorder.  These waveforms are lower in frequency than Beta waves and have higher amplitude, and result in more synchronous waveform patterns.  While in the Greek alphabet the letter Alpha comes before Beta, the lower frequency Alpha state comes after the Beta state as a result of the order in which they were discovered.  The existence of electrical energy in the brain was a discovery made in 1908 by Austrian physicist, Dr. Hans Berger.  Using his invention, the electroencephalograph (EEG), he discovered the first electrical waves in the brain and thus named them ‘Alpha’ waves.  It was not until years later that a higher level of brain activity was discovered known today as Beta waves.

Most people can achieve the Alpha state without the assistance of brainwave entrainment technology.  At 12Hz, you would begin to feel a release in tension built up in the body and experience a deeply relaxing muscular effect.  One researcher of the effects of brainwave harmonics describes the Alpha state as follows: 

A typical example (of the Alpha state) would be driving a car (how many times have you driven from work and barely remembered the journey?).” Secrets of Brainwave Harmonics Revealed

The Alpha state is also associated with deep concentration.  An artist working intently on a drawing, or reading deep into a good book are examples common to an individual in Alpha wave state.  In this state we are intensely focused and able to retain more incoming information and with greater detail.

Research regarding ROTE learning and memorization within the Alpha state can be a particular interest when revealing important information to an audience.  In such a case, entraining an audience to an Alpha state when important plot points of a play are revealed may result in a better understanding of the story.

Theta Waves (4 – 7.9 Hz)

Theta brainwave activity is related to the first (very light) stage of sleep, and has an even lower frequency and higher amplitude than Alpha waves.  Characteristic feelings associated with Theta waves are deep relaxation, idling, and drowsiness.  Some scientists believe that high amplitude Theta frequencies are responsible for most (if not all) psychic activity.  Results of studies performed using EEG testing suggest a correlation between tested subjects claiming psychic phenomena and ability to achieve consistent Theta wave production.

One reported (though unverified) use of Theta brainwave entrainment for a live audience exists as a tool for magicians.  One magician explains his application of audio entrainment technology in the following forum quote:

An early application I used was an audio frequency to make people "sense" a ghostly presence in the room. It was developed originally by the Military in WWII. The late Cleve Haubold (Van Cleve) was in MI and we developed the use back in the 80's as it applied to my stuff. It does work. I initially released it for sale on cassette as "The Visitor". To some people no sound was audible, some might notice a faint buzz in the background but nothing they wouldn't write off to just "room noise". However, some would get a "creepy" feeling that "something" was near them. Needless to say, they really had a ghostly experience. Jim Magus used it at a seance in Atlanta and it scared the (deleted adult word) out of some people. -- "The Magic Cafe"

Given the suggested use of this brainwave state, the effect could just as easily be applied to enhance a ghostly presence in a theatrical production.  For example, the presence of the Ghost of Christmas Past in a theatrical performance of the classic tale A Christmas Carol.  Further correlations between Theta waves and psychic phenomena will be explored in relation to isochronic tones.  In particular, the ethereal power of Theta frequencies provides a wide range of explorative use as applied to live stage performance.

Delta Waves (Under 4 Hz)

Delta brainwave activity has the highest amplitude and lowest frequency produced by the human brainCharacteristics of delta waveform are exhibited in very deep meditation or REM sleep.  A person untrained in meditative arts would more than likely only achieve Delta within a pattern of sleep, though some well-trained meditation experts are capable of remaining awake in such a state.

Delta waves may appear to have no benefit in a theatrical production.  A sleeping audience would be contrary to the goal of the performance.  Delta wave entrainment, however, is only effective when the listener has appropriately acclimated downward through the other levels of brainwave activity.  To do otherwise would cause discomfort, which depending on the theatrical application, may be an appropriate use of the technology.

Brainwave entrainment refers to the brain's electrical response to rhythmic sensory stimulation.  The human brain has a natural asymmetry, meaning one lobe is often more active than another while cognitive, sensory, and motor processes are being performed.  The result is a variety of frequencies produced by the brain at any given time, much like the timbre to an instrument.  Brainwave entrainment technology introduces pure forms of sensory stimulation (such as pure tones) in a rhythmic pattern to the brain.  The brain is susceptible to influence from these forms of rhythmic stimulation and will attempt to correct the imbalance of tones to match the stimulus, thus syncing or “entraining” to it.  There are several methods of producing the brainwave entrainment effect including photic (the use of strobes, LED’s and images), tactile (physical touching or tapping), and auditory (the use of pure tones and rhythmic beats).

Auditory brainwave entrainment can occur by three methods, each with its own set of advantages and disadvantages for theatrical use.  These methods are referred to as Isochronic Tones, Binaural Beats, and Monaural Beats.

Isochronic Tones

Isochronic tones are defined as manually spaced tones turning on and off in a precise pattern.  They are the harshest tones to the ear of the three methods, but also provide the strongest results for brainwave entrainment.  Isochronic tones are the oldest form of auditory brainwave entrainment techniques.  They date back to through centuries of tradition among ancient cultures from around the world in the form of a drum.  Melinda Maxfield points out the significance of the drum across world cultures in her research The Journey of the Drum, with examples regarding the shamanistic rituals of the Siberian people:

“The beating of the drum allows the shaman to achieve an altered state of consciousness or to travel on a journey. The drum is for example referred to as, ‘horse’ or ‘rainbow-bridge’ between the physical and spiritual worlds”Melinda Maxfield

The purpose of a shaman across several cultures is to act as an intermediary between the living and the dead.  In this example, the beating of the drum produces an isochronic tone capable of entraining the shaman and his followers to its rhythm.  As the rate of drum beat changes, the entrained listeners will sync with the rate of the drum, thus affecting their brainwave patterns.  An average shamanic beat of a drum can be established assuming between four to eight beats per second.  As stated earlier, the Theta brainwave pattern occurs in the range of 4 to 7.9 Hertz, thus providing a correlation between Shamanic drumming and the Theta brainwave pattern.  Since modern research also indicates a correlation between Theta wave production and the ability to experience psychic phenomena, one could begin to see a correlation between the shaman's drumming and his apparent connection to the spirit world.  Modern isochronic tones can be developed by use of computer generated oscillators and spaced appropriately to match the desired rhythm.  The turning on and off of these oscillators produces the rhythm that the brain will entrain to.

Isochronic tones are unique as an applicable form of entrainment technology for live theatre because they can be performer-produced.  They do not require pure tone frequencies, and are as simple to create as using any instrument that produces transient tones.  A 2009 production of Seneca’s Oedipus was performed at Western Michigan University with emphasis on traditional African music and dance.  The production incorporated live drumming.  Note that in this version of the classic play, the spirit of the dead King Laius is summoned back to life–a process that involved rhythmic drumming and chanting.  If isochronic tones produced by the drums were in-sync with the frequency range of Theta waves, then this production could have effectively used audio entrainment to enhance the ghostly presence of the dead King.  Given the appropriate circumstances, such as this production of Seneca’s Oedipus, isochronic tones can be incorporated into a production effectively while preserving the artistic integrity of the performance.

Monaural Beats

Monaural beats produce a similar effect to isochronic tones; they establish a rhythm that the brain becomes entrained to.  However, the beats are constructed in entirely different methods that yield a less intense stimulus to the sensory systems of the brain.  While isochronic tones can be produced using instruments with complex frequencies, monaural beats can only be produced using pure tone frequencies.  Furthermore, Gerald Oster’s study of auditory beats in the brain proves that the two pure tone frequencies required to produce a monaural beat must be of equal amplitude; else the potency of the beat on the brain is reduced.  This is why it is extremely rare to hear a monaural beat occur in nature.  A monaural beat is produced when two pure tones of equal amplitude and similar frequency are introduced to the brain.  Because the frequencies are similar, they interact with each other to produce a third frequency with a rhythmic modulation, or a beat. The frequency of this beat is easily calculated by subtracting the value of the lower frequency from that of the higher. Referencing the difference results in the frequency of the auditory beat.  Using an example from Gerald Oster’s study: 

“A tuning fork with a characteristic pitch of 440 hertz, or cycles per second (A above middle C on the piano), and another of 434 hertz, if struck at the same time, will produce a beat with a frequency of six hertz.”Gerald Oster

The apparent beat occurs as a result of phase cancellation.  If we examine the waveform of a 440 hertz tone and compare it with another of 439 hertz, we find that the waveforms begin in phase with one another.  Over the course of one second, however, the two tones will gradually fall out of phase.  At one point only within that second, the waveforms will be exactly out of phase with each other, resulting in auditory cancellation and zero amplitude (a brief moment of silence).  Using Oster’s example, with carrier frequencies of 440 hertz and 434 hertz this phase cancellation would occur 6 times per second, producing a 6 hertz modulation.

In regards to live theatrical production, monaural beats become a tool of particular interest for a sound designer.  These beats are not ideal to be created by an actor and require equal amplitude of both carrier frequencies, but this is a feat that any well-balanced audio system can overcome.  These beats can radiate from a single-point source and can be played in combination with other elements of sound.  The downfall is that the beats must remain at an audible level; that is to say if other sound elements are played loud enough to obscure the carrier frequencies, no beats will be detected.

Binaural Beats

            Binaural beats produce the lowest intensity beat of the three methods, but they have picked up the most publicity likely due to its ease on the ears and ability to remain effective even when concealed by white noise and masking effects.  A binaural beat occurs when two tones with frequencies just off-set from each other are introduced to the brain, one in the right ear, one in the left.  The theory behind beat production remains the same as a monaural beat, but the difference is in the way the brain interprets the carrier frequencies.  The brain interprets monaural beats externally, meaning the sound is combined outside of the body and enters both ears simultaneously.  The brain interprets binaural internally, in which the two carrier frequencies do not meet until they reach the brain.  As Oster again explains in his research:

“The lower auditory centers of the brain are in the medulla oblongata.  Nerve impulses from the right and left ears meet in the right of left superior olivary nucleus.  It is probable that binaural beats are detected here.”Gerald Oster

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Binaural beats can be useful in a theatrical setting because they have the ability to be interpreted at low amplitudes, even with additional sound elements matching the amplitude of the carrier frequencies.  Oster’s study shows that binaural beats are effective regardless of the amplitude of the carrier frequencies, proving the beats are equally effective even when one frequency’s amplitude is below the threshold of hearing. This means that binaural beat technology is much easier to incorporate into a sound design without requiring alteration of the sound effect to reveal the carrier frequencies.  Binaural beats, however, would require stereo headphones for each audience member in order to have the appropriate effect.  A November 2007 production of As Far As Thought Can Reach, the fifth installment of George Bernard Shaw’s Back to Methuselah was produced by the California Institute of the Arts School of Theatre that is an existing example of headphones being used in a live theatrical performance.  In this production, sound designer Nathan Ruyle provided a pair of headphones for every member of the audience.  Though the intent of this design was not for control of brainwave manipulation, the technical application of headphones is existing proof that binaural beat technology is a plausible element of theatrical sound design.

The use of audio brainwave technology for use in live theatrical applications remains, to my knowledge, a largely unexplored avenue of design.  Isochronic tones, monaural beats and binaural beats are three tools that, like a set of paintbrushes, could each serve a unique purpose in producing a unique sound design for a production.  By understanding the strengths and weaknesses of each technology, we gain an understanding of how each can be used (separately or in combination) in a live theatrical environment.  The way we respond to sound and music physically and psychologically is a crucial element of effective sound design.  Understanding how to manipulate that response through use of brainwave entrainment technology can be a useful tool in the arsenal of a sound designer.


As Far As Thought Can Reach. By George Bernard Shaw. Dir. Lars Jan.  Walt Disney Modular Theatre, California Institute of the Arts, Valencia, CA. November 2008.

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Oedipus. By Seneca. Dir. Joan Herrington. Williams Theatre, Western Michigan University, Kalamazoo, MI. March 2009.

Oster, G. (1973) Auditory beats in the brainScientific American, 229, pp. 94-102.

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