One of the most important things to learn in sound healing training is what brainwave entrainment is. Before we dive into the question, how brainwave entrainment is utilized in sound healing and sound therapy, let's learn what the term entrainment means in physics.
A generalized scientific definition of entrainment is “the effect of one system on another”.
In 1665 a Dutch physicist, mathematician, astronomer, and inventor Christiaan Huygens noticed that two pendulum clocks, mounted side by side on a wall, would eventually swing together in precisely synchronized rhythm. Huygens came up with the assumption that there must be some sort of connection between the activity of two pendulums. He conducted experiments to find out what caused the synchronization and found that a slight impulse, transmitted through the wall, caused two oscillators to finally find a mutual phase.
Entrainment is an interaction of different rhythms within one system that are coming to a common rhythm.
A necessary condition for one system to entrain with another: the first has to be sufficiently powerful to overcome the second. The proximity of two interactive systems is an important consideration. The power diminishes as distance increases.
Another condition for entrainment to take place is that the first system must be at a constant frequency or amplitude (rhythms must be constant and regular). Also, the entrained system has to be capable of achieving the same vibratory rate as the entraining one.
For systems with sufficiently similar natural resonant frequencies, entrainment will always shift toward the stronger resonator. Just as all gravitational bodies tend toward their mutual center of mass, vibrating systems tend toward the integration of rhythms. The system with stronger energy is harder to interrupt, therefore it will entrain the system with less energy.
*The concept of entrainment is different from resonance. Resonance refers to “echoing” or re-sounding a certain pitch, while entrainment is the alignment of rhythms.
In our lives, rhythm is everything. The very first rhythmic expression that is imprinted in every person is the heartbeat of one’s mother. This rhythm has probably shaped our consciousness.
There are sixty rhythmic clicks in one minute, sixty minutes in one hour, and twenty-four hours in one day. However, everyone has a different sense and interpretation of what the rhythm of life is. For the same person, it changes so many times even during one day. When we are busy, time flies, and it appears completely different when less is happening. In our lives, the sense of rhythm is manifested through our actions. There is a fast rhythm for action and a slow one for rest. We are masters of dictating those rhythms, and everyone has his own perception of what the right rhythm of life is. However, there are some rhythms that we share in common, and they are called internal periodicity.
Molecular, cardiovascular, respiratory and brain patterns are examples of internal rhythms. These rhythms set our activities and vice versa – our activities set our internal rhythms.
In music, rhythm designates the movement of musical composition in time. This element of music is most closely related to body movement and physical action and is called “the heartbeat of music”. Actually playing music consists of coordinated, rhythmic movements of a musician that are subsequently transmitted to a musical instrument and then to the listener.
One of the most highly researched phenomena in the field of rhythmic entrainment is the natural interconnection between the external rhythms and the body's motor skills. Using external rhythms mindfully could alter major body pulses, allowing us to be in an optimal state for specific activities. Whether sleep, emotional release, or high mental productivity is the goal, rhythmic entrainment is a way to accelerate or to slow down. If one feels out of sync, one can bring oneself back to the center with rhythm.
It is primarily because of entrainment that music alters the functioning of the nervous system. If the mental and emotional states of the listener are not affected by an external rhythm, there will be no change in heart and breathing rates.
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