When you play two separate frequencies in each ear, say 140 Hz and 149 Hz, the difference in frequency is 9 Hz. Your brain compensates for this difference and a third tone of 9 Hz is experienced. This will result in your brain being lowered or raised and tuned into the desired frequency. This is how binaural beats are produced. Headphones are essential for this to work.  
Sensorimotor rhythm (SMR) is one final type of brainwave that has been studied. SMR, also known as low beta, is a type of brainwave, which occurs in the sensorimotor cortex, in the 12 to 15 hertz range when that area of the sensorimotor cortex is idle and immobile. The purpose of SMR brainwaves is not well understood, but some neurofeedback practitioners report training to increase SMR brainwaves can be beneficial for people with autism, epilepsy, ADD, insomnia, drug addiction, and as an aide to better manage stress.
I was failing to achieve deep physical relaxation and looking for ways to shift my consciousness. After trying out many ‘solutions’ - including some truly bizarre ones - I decided to stop for a while and take a break before my next attempts at astral projection. That’s when I was recommended X. I must say it has been instrumental in helping me enter the state of relaxation and vibration necessary to a satisfactory OBE.
Gamma waves are the fastest of the brainwave frequencies (high frequency band of brainwave activity) which signifies the highest state of focus possible. They are associated with peak concentration and the brain’s optimal frequency for cognitive functioning – the 40 Hz frequency corresponds to a Schumann resonance band and many scientists, including Nobel Laureate Sir Francis Crick believe that it may be the key to the act of cognition. The Gamma state relates to simultaneous processing of information from different brain areas; information passes very rapidly.

Once you begin to experience the beneficial aspects of brainwave entrainment, you may be tempted to have these tracks playing all the time during your waking and sleeping hours. This is NOT advisable, nor is it necessary. Remember, brainwave entrainment is exercise for your brain so your brain will need to rest and integrate the new changes that your entrainment regime is creating.

Music therapy has shown numerous health benefits for people with conditions ranging from mild (like stress) to severe (like cancer). When dealing with stress, the right music can actually lower your ​​​blood pressure, relax your body and calm your mind. Here are some suggestions of different types of music to listen to, and how to use music in your daily life for effective stress management.
Theta is very subtle. It is one of the most elusive and extraordinary brain states you can explore. Theta is a state of somnolence with reduced consciousness; you are neither fully awake nor asleep yet. It is also known as the “Twilight state” or “Stage 1 Sleep” which you normally only experience fleetingly as you wake or drift off to sleep. In the Theta brain state, your senses are withdrawn from the external world and focused on signals originating from within.
John Dupuy is the CEO of iAwake Technologies and travels internationally to teach and inspire on the subjects of Integral Recovery, Integral Transformative Practice, and the use of brainwave entrainment technology to deepen one’s meditation practice and in the treatment of addiction, depression, and PTSD. John is the founder of Integral Recovery® and his book Integral Recovery: A Revolutionary Approach to the Treatment of Alcoholism and Addiction  won the 2013 USA Best Book Award. John also hosts interviews with leading innovators in the spiritual technologies field on Spiritual Technologies 2.0 Live and co-hosts the popular Journey of Integral Recovery podcast.
The Frequency following response (FFR), also referred to as Frequency Following Potential (FFP), is a specific response to hearing sound and music, by which neural oscillations adjust their frequency to match the rhythm of auditory stimuli. The use of sound with intent to influence cortical brainwave frequency is called auditory driving,[39][40] by which frequency of neural oscillation is 'driven' to entrain with that of the rhythm of a sound source.[41][42]
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.