Clinical testing of Brain Sync programs resulted in a record-breaking 87% success rate. They are offered to patients at America's most prestigious hospitals such as Sloan Kettering and Dana Farber Institutes. EEG studies conducted at Harvard Body Mind Medical School, and UCLA concluded that Kelly Howell's Brain Wave Audio Technology® prompts brain activity into extraordinary body-mind states. Vist our Research Findings page for a full list of articles from the Harvard Medical School, the U.S. National Institutes of Health and Psychology Today that concur: the benefits of guided meditation, binaural beats, brainwave entrainment and positive subliminal messaging are real and profound. To learn more see this article about brainwaves in Scientific American.
Alpha (12hz – 8hz) – Awake, but deeply relaxed. Simply closing your eyes will produce alpha brainwaves. This category is associated with daydreaming, visualization, imagination, light meditation. Brainwave expert Anna Wise called the alpha range the bridge between beta and theta. (More information can be found in Wise’ book The High-Performance Mind)
As somewhat of a modern mystic, I have studied altered states of consciousness, but due to my monkey mind, I have only been able to experience them to a very minor degree. I have tried so many methods of meditation to little avail. But I became aware that I would not be able to progress in my spiritual life if I could not achieve at least a modicum of success in meditation.
Isochronic tones are the most recent and advanced method for brainwave entrainment audios. With isochronic tones, the same intensity is used for all tones, but they pulsate on and off at different rates. The speed, pattern, and rates of these tones can be changed and altered throughout the recording, and the brain will follow them into desired states. The use of isochronic tones opens up the ability to lead the brain into highly specific states, at specific speeds and intensities. This has opened up the doorway to producing both dominant and subdominant waves(i.e. an alpha brainwave state with subdominant theta waves), and the ability to lead the brain through different waves, at specific speeds (i.e. holding the brain in an alpha state for 10 minutes, then dropping it through theta for 20, and holding it in delta for five before bringing it back into alpha at the end of the recording.) This allows thousands of different possibilities in training the brain, and also makes the process of listening to these types of audios more natural, and more powerful. 
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

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]