When some people first hear the term “auditory bilateral stimulation” they want to know if it’s anything like binaural beats. Anyone asking this question obviously knows something about “healing music”, since binaural beats are a pretty specialized concept. However, since the vast majority of people are not familiar with either term this brief discussion about the relationship between binaural beats and bilateral stimulation may be helpful all around.
Let’s start with auditory bilateral stimulation since it is the reason Alternating Sounds, LLC even exists. This is simply the rhythmic alternation of sound back and forth across the left and right hemispheres of the brain, using headphones or ear buds. People use this gentle back-and-forth swaying of sensory input to activate deep brain processing which is then used to enhance creativity, insight, confidence and performance. Bilateral stimulation is also used by EMDR or Brainspotting therapists to heal traumas and help bring about many other therapeutic gains.
Binaural beats, on the other hand, are pulsations or beats that a brain hears when two tones with slightly different frequencies are played separately into each ear (hence the term "binaural"). The number of these beats per second is equal to the difference (measured in hertz) between the two frequencies. For example, if you listen to a 300Hz tone in your left ear and a 312Hz tone in the right, your brain will “hear” a pulse or beat that repeats 12 times a second.
The conventional wisdom, backed up by some scientific support, associates certain frequency ranges of binaural beats with the following mental states:
Gamma (greater than 30Hz) - This frequency range is associated with working memory and the learning functions of the higher cortex.
Beta (13 to 30 Hz) - This is the predominate frequency range of a brain that is active, busy and intensely concentrating.
Alpha (8 to 12Hz) – This is the frequency range often associated with the state of “flow”, i.e. when the mind is alert but relaxed, “zoned in”, deeply focused and highly productive.
Theta (4 to 8 Hz) – This frequency range is generally associated with deep relaxation, meditation, creativity, hypnotic states and active dreaming.
Delta (less than 4 Hz) – This very slow frequency range is associated with deep, dreamless sleep.
Both bilateral stimulation and binaural beats are used for many purposes related to personal growth and development. However, bilateral stimulation is unique in the fact that it is used in Brainspotting and EMDR, as mentioned above.
The next topic to address is whether binaural beats and bilateral stimulation can be used together. If both are helpful to bring a listener's brain to an optimal state, wouldn’t a more positive outcome occur if these two sonic enhancements are combined?
The answer is that true binaural beats cannot occur with bilateral stimulation. This is because of the necessity for each ear to hear a different tone without any cross-over between channels, which is a core characteristic of bilateral stimulation, especially when the bilateral strength (bls) is 100/0, i.e. traveling all the way back and forth so that at times one ear is not receiving any stimulation).
However, an effective work-around that is a near-equivalent of binaural beats is to create an ongoing series of auditory pulses per second that correspond to the frequency range(s) that are desired. Here’s how it works: remember that a true binaural beat is created by mixing (for example) a 496 Hz tone with a 484 Hz tone, which results in 12 binaural beats per second. So by simply adding a percussive tone that occurs 12 times in a second it is possible to mimic the equivalent of a 12 Hz binaural beat. This work-around is called an “isochronic tone/beat”.
Alternating Sounds, LLC seems to (so far) be the only company to include binaural beats in some of our bilateral music. We generally start these soft isochronic tones in the high alpha to low beta range (about 12 to 14 Hz) and then gradually reduce the frequency over the course of a few minutes to the low theta range of about 4 Hz. This process is intended to transition the listener’s brain away from focusing externally toward a more relaxed, receptive, meditative and free-associative state of mind.
For the sake of completion it’s worth noting what are known as “monaural beats”. These occur by playing two tones with different frequencies through a speaker at the same time. (Binaural beats that occur in headphones become monaural beats when played through speakers.) Since bilateral stimulation only occurs when using headphones or ear buds, the use of monaural beats is not applicable, just worth mentioning.
There is a lot more information from various online sources that describe binaural beats, isochronic beats and monoaural beats in significantly more detail. The purpose of this short overview is to describe the relationship of these effects to bilateral stimulation. The blog post "Advice for Creating Bilateral Stimulation Music" includes the suggestion of incorporating very soft isochronic beats into the production mix.
We hope that this brief overview of the relationship between binaural beats and bilateral stimulation has been helpful. Check out the rest of this website for lots more information related to auditory bilateral stimulation, including the many special qualities of the music on the Alternating Sounds, LLC label.