There’s an aesthetic element to the music and there are a lot of drone-based sounds and time-stretched sounds, deep, rich bass sounds—there’s a spectrum of sounds within there—and what’s more, there’s a load of 3D processing that goes on to ensure that the mind doesn’t become habituated to them. There’s also a constant, subtle sense, a slow and gradual sense, of the sounds shifting around. And, there are layers of binaural beats.
This extremely popular app features over 90 tones and music to help you achieve your desired state of mind. While other apps focus on sleep, memory and meditation, this app also includes programs for increasing psychic abilities, contacting spirit guides, and enhancing yoga. This subscription-based application is right for you if you’re looking for an experience specifically designed for your health, spiritual and emotional desires.
When delta waves are present, our awareness of the external world decreases and shuts off. People with ADD have problems with delta waves occurring when they are trying to focus, and focus and attention become increasingly impossible with stronger delta waves. Studies show a reduction of anxiety, improvements in insomnia, and elimination of headaches when people engage in sessions of delta brainwave entrainment.
Theta brainwaves in the frequency range of 6 to 9 hertz are known as thalpha waves because of their proximity to alpha waves. They are seen during states of high suggestibility, during hypnosis, and during paranormal experience and are also connected to an increase in human growth hormone (HGH) levels and higher blood flow to the brain. Theta brainwaves sit between the realms of the subconscious and conscious mind, making them an especially useful brainwave state for developing creative thinking, working through emotional problems, and integrating subconscious and conscious experience. 

I have many new age, meditation, classical and jazz cds that I use for relaxation. This Steven Halpern cd is now my favorite one. I can listen to it for hours on end while I read, write, use the computer, or just veg out on the couch at home or lounge at the pool. I especially love the tracks with the ocean wave sounds mixed in with the electronic music. I definitely am in the theta brain wave state while listening to it, and I know that's the reason it is so much more soothing than any other cd that I own. It is really great for eliminating any anger or anxiety that I may be feeling. I believe it's also improving my sleep. I give this cd the highest possible recommendation!

Most capsules either contain powdered, dry herbs, or a tiny bit of liquid extract (gel caps). Tablets are powdered herbs that are held together by pressure and other chemicals. The beauty of liquid extracts, or "tinctures," is that they absorb quickly and the body receives the full benefit of the plant in a very bio-available solution. Liquids also allow you to customize your serving freely so you can best meet your needs at the time. Liquids are inexpensive and easy to swallow. The droppers and pump top dispensers are also convenient for when you're on the go.

I have read something different about theta waves and learning languages. A University of Washington study tested students resting brainwave activity before learning French. They found that students with a higher amount beta/gamma and a lower amount of delta/theta activity were better at acquiring a second language. When you are dominant in theta, that is the lowest and most deeply relaxed awakened state you can be in. I think it would be much harder to really concentrate, fully understand and learn new information while in a theta state, so I would personally consider using theta while studying.
This is an extreme example, naturally, but the idea holds true even in situations that are not as extreme. This ties in very closely with Point #4 above. When you’re wishing to combine meditation and brainwave entrainment, if you’re practicing a meditation technique but not really paying attention to what you’re doing, or perhaps you are performing the technique wrong, whilst allowing your mind to drift off to wherever it takes you, it should come as no surprise that the entrainment track is not helping you achieve a state of meditation. That’s because in fact you aren’t really trying to enter meditation or because you’re specifically engaging in activities that prevent you from getting there.
Gamma brainwaves occur during creative thinking and processing of memory and language and in many learning activities. These brainwaves are not present at all when a person is under anesthesia, but return as soon as the person becomes conscious again. Multiple scientific studies have shown gamma brainwave entrainment to be helpful for reducing distractibility, improving short-term memory, improving motor coordination, and relieving migraine headaches.
“A quite different phenomenon results when stereophonic earphones are used and the signals are applied separately to each ear. Under the right circumstances beats can be perceived, but they are of an entirely different character. They are called binaural beats. . . . Binaural beats require the combined action of both ears. They exist as a consequence of the interaction of perceptions within the brain.”

♥ When I learned about Binaural beats and found out how you can influence your state of mind, I utilized them for most of my college studies. I play 16Hz Beta waves behind my favorite study music. I've been using them for 3 years now and they help me stay focused longer. Just make sure you have quality headphones that can reproduce the frequencies accurately. 2Hz does make a difference with an EQ.
Although there is a general stress response pattern, there can be variations in the response according to the characteristics of the stressor (10). Individuals tend to respond differently based on the familiarity of the stressor. For example, the perceived level of stress and physiological response when giving a presentation to a group of work colleagues will likely be less than when presenting to an unfamiliar group. The stress response also varies depending on the level of perceived control one has over the stressor (10). If there is a way for one to actively cope with the stressor that is reasonable, then the individual usually perceives more control over the situation. Consider an individual who has to take a certification examination for work and has 6 months to prepare. He can adjust his schedule to accommodate study time. However, waiting for medical test results that show whether one has a serious illness does not allow a sense of control over the stressor, and the individual passively endures the stressor or may try to avoid the stressor. With this uncontrollable type of stressor, there is a more negative reaction with greater productions of cortisol, which can have damaging health effects because of the suppression of immune function (10).
When we first use brainwave entrainment, we may not have anything specific in mind that will happen, but we hold a general expectation that “something” should happen. As we begin the process of entrainment we are on high alert looking for any little indication that something is happening. Pretty soon we identify some feeling or twitch or unusual perception. The moment we focus on whatever it is, the act of focusing on it magnifies the thing. Since we were already viewing the situation with an expectation that it was the entrainment that was going to produce some sort of result, we automatically associate whatever our phenomenon is with entrainment.
Changes in neural oscillations, demonstrable through electroencephalogram (EEG) measurements, are precipitated by listening to music,[20][21][22][23][24][25] which can modulate autonomic arousal ergotropically and trophotropically, increasing and decreasing arousal respectively.[26] Musical auditory stimulation has also been demonstrated to improve immune function, facilitate relaxation, improve mood, and contribute to the alleviation of stress.[27][28][29][30][31][32][27][33] These findings have contributed to the development of neurologic music therapy, which uses music and song as an active and receptive intervention, to contribute to the treatment and management of disorders characterized by impairment to parts of the brain and central nervous system, including stroke, traumatic brain injury, Parkinson's disease, Huntington's disease, cerebral palsy, Alzheimer's disease, and autism.[34][35][36]