The brain is composed of millions of specialized cells called neurons. Neurons send signals to other neurons using electro-chemical messengers called neuro-transmitters that attach to receiving sites located on the neurons themselves. There is a space between the end of the neuron and the receptor called the synaptic gap. As neuro-transmitter chemicals move across this gap, a small electrical charge is created. 

A more extensive study of over 100 participants who were undergoing general anesthesia for a day procedure, reported a decrease in pre-operative anxiety. The participants in this study listened to 30 minutes of binaural beats before surgery, but the researchers noted that people experiencing high levels of pre-operative anxiety could listen to binaural beats for up to 1 hour before anesthesia to reduce levels of anxiety.
Meanwhile, the therapeutic benefits of listening to sound and music is a well-established principle upon which the practice of receptive music therapy is founded. The term 'receptive music therapy' denotes a process by which patients or participants listen to music with specific intent to therapeutically benefit; and is a term used by therapists to distinguish it from 'active music therapy' by which patients or participants engage in producing vocal or instrumental music.[37] Receptive music therapy is an effective adjunctive intervention suitable for treating a range of physical and mental conditions.[38]
“The great neuroscientist W. Gray Walter carried out a series of experiments in the late forties and fifties in which he used an electronic stroboscopic device in combination with EEG equipment to send rhythmic light flashes into the eyes of the subjects at frequencies ranging from ten to twenty five flashes per second. He was startled to find that the flickering seemed to alter the brain-wave activity of the whole cortex instead of just the areas associated with vision. Wrote Walter, “The rhythmic series of flashes appear to be breaking down some of the physiologic barriers between different regions of the brain. This means the stimulus of flicker received by the visual projection area of the cortex was breaking bounds— its ripples were overflowing into other areas.”
I have been making relaxation recordings for mental self help and health improvement since 1979. As a pathfinder in EEG ( brainwave monitoring and entrainment ) I understand totally the effects of sound and music on the human mind and body. The recordings offered from your website are without doubt some of the most effective I have ever used and recommend them to my clients whole heartedly
Meditation Begins • Mind Chatter Slows Down • Great For Learning & Studying • Creative Ideas Flow • Reverse Brain’s Aging • Habits, Fears, Phobias Melt Away • Calm & Peaceful • First Layer Of Subconscious Mind • Gateway To Deeper Mental States • Advanced Focus • Relaxation Begins • Serotonin • Endorphins • Good For Anxiety, Depression, Stress, Panic • Mind Power • Happiness • Confidence
Entrainment is like priming the pump of meditation. It doesn’t “cause” meditation any more than pouring that little bit of water into the pump initially “causes” water to appear in the well. The water was already there. The conditions for the pump to do its job just needed to be set up. What entrainment does is to create the conditions and the internal environment typically associated with meditation. You could get to that point without entrainment, certainly, but the entrainment allows you to get there quicker, more consistently, and to remain there for longer periods of time than you would ordinarily be capable of doing on your own.

Maybe a favorite popular song, a certain piece of Classical music, a raucous dance beat, the pulse of Reggae, Indian, or African drums, or the chanting of Gregorian or Tibetan monks, but you probably know how the sound of music, drumming, or chanting is capable of transporting you into an altered and joyous state of mind and uplifting your spirits.

Brainwave entrainment is a colloquialism for such 'neural entrainment', which is a term used to denote the way in which the aggregate frequency of oscillations produced by the synchronous electrical activity in ensembles of cortical neurons can adjust to synchronize with the periodic vibration of an external stimuli, such as a sustained acoustic frequency perceived as pitch, a regularly repeating pattern of intermittent sounds, perceived as rhythm, or of a regularly rhythmically intermittent flashing light.