Consider the following analogy. Imagine a ballroom full of people dancing together. When the music changes to a faster tempo, the dancers move faster in response to this. When a slower piece of music is played, the dancers’ rhythm slows down as well. In a similar way, the frequency of your brain will change in response to the frequency of the binaural beat that it is exposed to. For example, a person who is in a state of very deep meditation may have a dominant brainwave frequency of 5 hertz, so by listening to a binaural beat with a frequency of 5 hertz you can entrain your own brainwaves to a similar state.
In order to understand brainwave entrainment you first have to understand something about brain waves and electroencephalograms (EEG). Neurons are cells that communicate with each other through electrical conduction. When a neuron fires it creates a small electrical and magnetic field. These fields are far too small to measure by placing electrodes on the scalp, or even on the surface of the brain. The only reason we can detect the electrical fields of the brain is because many neurons are firing together – in synchrony. All brain waves that are measured by an EEG, therefore, represent a large group of neurons firing together.
You may not always be in the mood for meditation when your thoughts are racing, though it is a powerhouse of a stress reliever; you may sometimes face relationship stress that isn't as well-managed by breathing exercises (another highly effective stress reliever) as it might be by learning communication techniques. Guided imagery is fantastic for before bedtime while games are an optimal stress reliever to share with friends.
With the binaural beats, this may be difficult to do since you need to listen to the twin frequencies and allow your brain to create a third one to bridge the gap. Ideally, you will be listening to these beats through headphones so carrying out other work may be challenge. However, with isochronic frequencies, the tone can be heard without headphones which means you can run the mp3 with a speaker and allow it to play in the background as you carry out your work. Of course, activities such as driving or operating heavy machinery should NOT be undertaken when you are listening to these tones because your attention is shared between the two tasks. Tasks like gardening or sewing or cooking can be done while your brainwave entrainment music is playing.

When the track is over you can continue to meditate without the help of the entrainment track.  When you are ready to get up, thank your Higher Self for the experience and remove your blindfold, keeping your eyes closed.  Stay seated with your eyes closed for a few moments, then slowly open them and take a moment to let your eyes adjust to your environment’s light. 

Resonant entrainment of oscillating systems is a well-understood principle within the physical sciences. If a tuning fork designed to produce a frequency of 440 Hz is struck (causing it to oscillate) and then brought into the vicinity of another 440 Hz tuning fork, the second tuning fork will begin to oscillate. The first tuning fork is said to have entrained the second or caused it to resonate. The physics of entrainment apply to bio-systems as well. Of interest here are the electromagnetic brain waves. The electrochemical activity of the brain results in the production of electromagnetic wave forms which can be objectively measured with sensitive equipment. Brain waves change frequencies based on neural activity within the brain. Because neural activity is electrochemical, brain function can be modified through the introduction of specific chemicals (drugs), by altering the brain's electromagnetic environment through induction, or through resonant entrainment techniques.

“Stress” is a commonly used term, and it is often used with different meanings. The standard definition for stress that will be used in this article is the disruption of the body’s homeostasis or a state of disharmony in response to a real or perceived threat or challenge (8). The threatening or challenging situation is referred to as a “stressor.” When a person encounters a stressor, the body prepares to respond to the challenge or threat. The autonomic nervous and endocrine systems respond by producing the hormones epinephrine, norepinephrine, and cortisol. The result of this hormone production is a cascade of physiological reactions that make up the stress response. Epinephrine and norepinephrine are involved in the initial changes that take place to prepare the body to react and to prepare for a challenge. These responses include increases in heart and respiration rates, blood pressure, perspiration, and energy production (8). There also is a suppression of immune function, production of β-endorphin (the body’s natural pain killer), and increased acuity of the senses. These changes make up the fight-or-flight response, which prepares the body to cope with the stressor. If the stressor is perceived as negative or more as a threat than as a challenge, cortisol production is increased. Cortisol is involved in energy production but also suppresses immune function.
If brainwave entrainment leaves you with unwanted side-effects (see below) or discomfort, you’re probably encouraging a range of brainwaves that are already excessive in some area of your brain. The way around this is to get a brain map to see what your brain’s strengths and weaknesses are, and see what (if any) brainwaves could use some encouragement.