More information on neural entrainment can be found here: https://www.anthonysommer.com/blog/neural-entrainment
Neural entrainment is also known as brainwave entrainment or brainwave synchronization. It is the theory that our brains have a tendency to synchronize themselves to external stimulation, which could include auditory, visual, tactile or electromagnetic stimuli.
It is believed that the human brain contains approximately 80+ billion neurons which communicate with each other to form our thoughts, emotions and behavior. When our neurons communicate in mass, it produces a synchronized electrical pulse known as a brainwave. Our brainwaves can align with an external stimuli, and as a result we can stimulate our brains in ways that could positively effect our psychology and physiology. Using this method we could alter the state of our consciousness in ways that we would usually have difficulty reaching. Entrainment is an effective method which allows you to experience what these states feel like, and how they affect the body.
The most common forms of auditory induced neural entrainment are produced through the usage of monaural, binaural and isochronic tones.
- Monaural audio is commonly a sine, square or sawtooth wave distributed through a single audio channel, opposed to binaural audio where it uses both left and right stereo channels. Headphones are not required, but some may prefer it.
- Binaural audio is composed of a left and right channel, which plays two different frequencies. The difference in each frequency creates a pulse modulation rate which is the key of binaural audio. For example, if you were to use a sine wave of 440 Hz on the left side, and 432 Hz on the right side, you would have a pulse modulation rate of 8 Hz. Headphones are not required, but are highly recommended.
- Isochronic audio is a wave which is modified by pulse width, a fade time, a modulation frequency and depth. In simplest terms it is a tone which is being turned on and off rhythmically. Headphones are not required, but some may prefer it.
There are five primary brain wave ranges. They are known as Delta, Theta, Alpha, Beta, and Gamma waves.
Delta waves are the slowest of all and range between 0 - 4 Hz. We experience these waves naturally when we are in the deepest of sleep or meditative states. These waves stimulate healing and regeneration and as a result are vital in the maintenance of health and psychological well being. This is the state of sleep that makes individuals feel well rested, and clear-headed. It is reported that these brain waves are an ideal choice to access your subconscious for deep reprogramming and for the surfacing of the unconscious.
Theta waves are faster than Delta waves, and range between 4 - 8 Hz. We experience these waves when sleeping or during deep meditation. These waves are the "twilight" state normally experienced between waking and falling asleep. They are beneficial for meditation, learning, memory, sub-conscious organization, intuitive thinking and trance states. It induces a feeling of a "dream like" state.
Alpha waves are faster than Theta waves, and range between 8 - 12 Hz. We experience these waves in meditative states or wakefulness. These waves promote a presence of mind, clarity, creativity, and stress reduction. It is a resting state for the brain and aids mental coordination, mind/body integration and the learning process. Many report this as an especially pleasureable state of mind.
Beta waves are faster than Alpha waves, and range between 12 - 38 Hz. This is the range of our normal wakeful state of consciousness. This is when we are wakefully cognizant, attentive, focused, and most eligible to do tasks that require full attention. This is great for discernment, problem solving, and forming complex abstract thoughts. An over-abundance of Beta waves will result in fatigue or exhaustion.
Gamma waves are the fastest brain waves, and range between 38-42 Hz. This is the range of peak concentration and cognitive function. It is also useful for everything that Beta waves specialize in, and like Beta waves, an over abundance of Gamma waves will result in fatigue or exhaustion.
Noise can be a great addition to neural entrainment. It appears to alleviate discomfort and reverse undesirable effects related to excess usage of a particular wave range. It is often described as being refreshing and revitalizing, particularly when used in combination with nature sounds such as flowing water. Noise can also be used as a sound barrier. The brain uses noise to tune out any background noises lower than it's amplitude. It also seems to help the brain 'tune out' it's auditory stimuli. When a user listens to noise their brain cannot clearly process all of the sound frequencies being heard, so it will zone out naturally because it is overwhelming to even attempt. This is analogous to the idea of a room with a thousand people talking simultaneously at the same volume. You would not be able to focus on any conversation, and you would instinctively hear it as background noise instead. It is similar in effect to cooking an aromatic recipe. You would typically smell everything together, rather than each specific ingredient separately.
The primary forms of noise that are commonly used are: white, pink and brown noise.
Reported benefits of white noise: beneficial sound barrier (useful for distractions), improved productivity, improved concentration and focus, mild tinnitus relief, ADHD assistance.
Reported benefits of pink noise: improved concentration and focus, soothing effects, improved memory, improved productivity, improved sleep and alleviated headaches among other beneficial effects.
Reported benefits of brown noise: sleep/rest quality improvement, superior tinnitus relief, improved concentration and focus, improved memory, increased reading comprehension, relaxation aid, meditation aid, calm nervous pets and children and a comfortable but useful sound barrier among other beneficial effects.