The Transparent Corp forum – This forum is an invaluable resource for any brainwave entrainment user or enthusiast.  Most of the feedback is obviously focused on the Transparent Corp software, but with over 20,000+ posts now you can find answers to the whole array of brainwave entrainment questions on there.  (UPDATE: Sadly, the Transparent Corp forum has now been taken offline)
Most of these websites give some brief explanation of entrainment. The example you hear most often is that of Dutch polymath Christiaan Huygens, who in 1665, hung two pendulum clocks next to each other on a wall. He noticed that the pendulums eventually matched each others' frequency, but always in antiphase, opposite to each other, as if canceling each other out. He'd try disturbing one or setting them in sync, but they'd always return to the same antiphase synchronization. Huygen's experience is widely touted on binaural beat websites as a demonstration of how systems can become spiritually connected through some energy field. However, they misunderstand what happened, and have not read the full story. Huygens also tried taking one clock off the wall, and as soon as they were no longer physically connected to one another via the actual wall, the effect disappeared. It was not the proximity of the clocks to one another that created the entrainment; it was their physical, mechanical connection to one another. As each pendulum swung it imparted an infinitesimal equal and opposite reaction to the wall itself. With two clocks on the wall, the system naturally sought the lowest energy level, according to the laws of thermodynamics; and both pendulums would thus swing exactly counter to each other, minimizing the system's total energy.
Most of the tips we’ve suggested provide immediate relief, but there are also many lifestyle changes that can be more effective in the long run. The concept of “mindfulness” is a large part of meditative and somatic approaches to mental health, and has become popular in modern psychotherapy. From yoga and tai chi to meditation and Pilates, these systems of mindfulness incorporate physical and mental exercises that prevent stress from becoming a problem. Try joining a class.
Thanks Lorita. There hasn’t been any isochronic tones research that I’m aware of, for anti-aging, fat loss or attracting people, or any significant anecdotal feedback. You could combine positive affirmations or hypnosis scripts with isochronic tones to try and change habits and that could help with fat loss or build confidence to attract people. But it would be the affirmations and hypnosis doing most of the work, the isochronic tones would just be used to help relax the listener and put them in a more suggestible state. I don’t believe isochronic tones can affect those things, without being used in combination with some kind of vocal mental programming.
This music encourages a state of delta relaxation. Delta brainwaves are most prevalent during deep, dreamless sleep. The delta state is a mostly unconscious state that is essential to one’s physical, emotional, psychological and spiritual wellbeing. People who are able to achieve a state of delta relaxation through meditation will sometimes describe spiritual encounters and out of body experiences. The delta state is perfect for inducing profound spiritual experiences, healing and deep subconscious repatterning. Delta frequency brainwave entrainment music is also a fantastic cure for insomnia.
Hi EJ, at the moment, there hasn’t been any research to give an indication of how long you should or shouldn’t listen for. Over time, I’ve seen people use my tracks for longer and longer. I started off providing 30-minute study tracks, but through demand, I extended them to 3-hours. I know from the many thousands of comments I’ve had on YouTube that a large number of people play those 3-hour tracks on repeat, or listen to different ones, one after the other throughout the day. I’ve also seen apps where you can play tracks like mine on continuous repeat. So it’s common for people to listen to them all day while they are studying.
It might seem obvious that you’€™d know when you’€™re stressed, but many of us spend so much time in a frazzled state that we’ve forgotten what it feels like when our nervous systems are in balance: €”when we’€™re calm yet still alert and focused. If this is you, you can recognize when you’re stressed by listening to your body. When you’re tired, your eyes feel heavy and you might rest your head on your hand. When you’re happy, you laugh easily. And when you’re stressed, your body lets you know that, too. Get in the habit of paying attention to your body’€™s clues.
This phenomenon is best known in acoustics or music, though it can be found in any linear system: "According to the law of superposition, two tones sounding simultaneously are superimposed in a very simple way: one adds their amplitudes".[2] If a graph is drawn to show the function corresponding to the total sound of two strings, it can be seen that maxima and minima are no longer constant as when a pure note is played, but change over time: when the two waves are nearly 180 degrees out of phase the maxima of one wave cancel the minima of the other, whereas when they are nearly in phase their maxima sum up, raising the perceived volume.
This is not to say that entrainment cannot produce some physical effects, particularly negative ones. It is possible to induce epileptic seizures using entrainment, especially visual entrainment that employs flashing lights. That’s why people with seizure disorders are uniformly told to consult with their health care provider before using entrainment if they have a seizure disorder or some other serious medical condition.
Using a unique approach that combines the best methods from many different fields, the Neuro-Programmer 2 is an effort-free software application with unlimited potential and broad capabilities. Although it is incredibly simple to use, it remains the most effective self-help tool on the market today. Using NP2 is the single best way to achieve rapid and long lasting personal change.
Brain Wave Entrainment is any procedure that causes one's brainwave frequencies to synchronize with a periodic stimulus (sound, vibration or light) having a frequency corresponding to the intended brain-state (for example, to induce a trance, dreams, sleep or relaxation.) It is also called the Flicker-response because of how staring at a campfire or the flickering of a burning candle can lull you into a state of calmness and serenity. There was an extensive article on this phenomenon by Gerard Oster in Scientific American in 1973. It may sound novel, but in many ways, this is old tech.

For a few minutes a day, practice being mindful—focusing only on what's going on in the present —whether it's during your workout or taking a break from your work. Try taking a short walk and instead of thinking about what's worrying you, pay attention to your senses—what you see, feel, hear, smell. This can make a huge difference in your emotional and physical well-being when done daily.

The effects are strongest while you are listening to the tones because your brainwaves are synchronized and tuned into the frequency range you desire at that time.  After you've stopped listening the effects can still linger for a while afterwards.  The timescale will vary from person to person and be affected by what you do after you've stopped listening.
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]