Targeted hemispheric changes: Some speculate that specific alterations in brain waves can be made on an individual basis. In other words, you can target one frequency in one hemisphere (via the right ear) and another distinct frequency in the other hemisphere (via the left ear). The left ear affects the right hemisphere and right ear affects the left hemisphere.
Science, yes. Fiction, no. Every one of these results has been experienced and reported to us by participants in the program we’ve created around Holosync®, our proprietary version of this amazing audio technology. We call the program The Holosync Solution™, and believe me, it really will be the end of your search for a personal growth and mind development tool that really works.
This is probably the most popular choice of frequency. The theta state is a state of tremendous stress relief. The benefits associated with theta level relaxation include improved concentration, reduced hyperactivity and improved memory. While in a state of theta relaxation, one’s blood pressure, breathing and heart rate all slow to a much more restful and healthy level that promotes natural healing. During theta relaxation one may also experience vivid flashes of mental imagery as the mind opens to memories or subconscious information that is not available to the conscious mind during the normal waking state. The theta state is a very deep state of relaxation that is excellent for deep hypnosis and mental programming.
Jump up ^ Bittman, B. B., Snyder, C., Bruhn, K. T., Liebfreid, F., Stevens, C. K., Westengard, J., and Umbach, P. O., Recreational music-making: An integrative group intervention for reducing burnout and improving mood states in first year associate degree nursing students: Insights and economic impact" International Journal of Nursing Education Scholarship, Vol. 1, Article 12, 2004.
With digital upgrades, Berger’s machine is still in use today, known as an electroencephalography machine, or EEG. Berger used his machine to study the brains of psychologically normal and abnormal people and discovered the first brainwave, called the alpha wave and also known as the Berger wave, along with the faster beta wave, which he observed suppressing the alpha wave when subjects opened their closed eyes. 

If you're struggling to focus and feeling a bit tired and unmotivated while studying, you can help boost your concentration and energy levels by increasing Beta activity.  The SMR range is right at the bottom of the Beta range, so it's not too intense, and so is ideal for playing in the background and using as a general study aid.  If you are looking for something a bit higher for a more intense focus session, try my Study Focus isochronic tones session, which uses frequencies between 14-17Hz.
First discovered by biophysicist Gerald Oster at Mount Sinai Hospital in New York City, Brainwave Therapy sends pure, precisely tuned sound waves of different frequencies to your brain via stereo headphones. In his EEG research, Oster discovered that when different vibrations, or sound frequencies, are delivered to the brain separately through each ear (as with stereo headphones), the two hemispheres of the brain function together to "hear" not the external sound signals, but a third phantom signal. This signal is called a binaural beat, and it pulses at the exact mathematical difference between the two actual tones. For example, a signal of 100 Hz delivered to the left ear, and a signal of 107 Hz delivered to the right creates a binaural beat of 7 Hz that in this case falls into the Alpha range
Another small scale study with 30 children were entrained with a starting frequency of 14 Hz and ramped up to 40 Hz. Following the excitatory-based protocol, they were then given a protocol that started at 40 Hz and decreased to 14 Hz over 6 weeks. The results indicated that the children significantly improved in arithmetic abilities based on the WISC-III.
-Other Specialized Entrainment Methods: There are a few other things to consider like whether the audio creator uses binaural beats, monaural beats, or isochronic tones when appropriate for the desired effect of the audio. Or whether they use other entrainment methods as well, like volume modulation, pitch modulation, or panning from right to left of the headphones to further improve the immersion of the audio.

1) Theta Music Meditation from Unexplainable Store. Yep, you guessed it, this is a meditation MP3... with music. Boom. This is a nice, simple, powerful 20 minute session and (like all my recommendations) guaranteed 100% to work every time. Find yourself drifting away with this awesome recording, and start to reap the benefits of your underused theta brain waves. Simple and understated, my favourite.
The functional role of neural oscillations is still not fully understood;[6] however they have been shown to correlate with emotional responses, motor control, and a number of cognitive functions including information transfer, perception, and memory.[7][8][9] Specifically, neural oscillations, in particular theta activity, are extensively linked to memory function, and coupling between theta and gamma activity is considered to be vital for memory functions, including episodic memory.[10][11][12]