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.
The Delta brainwave is experienced by us every night in dreamless sleep. It is also experienced by advanced yogis and monks who can enter the Delta frequency during deep meditation. This frequency assists in both emotional and physical healing, as well as enhanced immune functioning, significant stress reduction, and even anti-aging benefits. The Delta frequency is a terrific way to experience deep repair on the physical, emotional, and psychological levels.

However, with this integration will come upheavals as the mind is forced to integrate areas of the brain that were previously sequestered. Repressed memories and unpleasant emotions from the past will often rise to the surface of the mind to be processed and healed. This is sometimes referred to as "processing the shadow" within one's mind and emotions.
Theta waves have another interesting characteristic. The Earth has a measurable resonance of 7.83 hertz known as the Schumann resonance. Because the Schumann resonance is a constant background frequency surrounding all life, it may play a special role in biological activity. The Schumann resonance frequency falls within the range of theta brainwaves and may have something to do with why these brainwave frequencies are so powerful. 
Why do you like to do these things? “I can escape from stress on my bike. My time on the bike gives me time to problem solve and consider all sorts of things. There are no interruptions from technology so it’s a peaceful time for me. I get to enjoy just being outside. This will sound crazy but sometimes I can ride for miles and not even remember the actual riding since I was ‘lost’ in my thoughts.”
That is generally where the science ends and the pseudoscience begins. A number of companies and individuals have then extrapolated from the phenomenon of entrainment to claim that altering the brain waves changes the actual functioning of the brain. There is no theoretical or empirical basis for this, however. Entrainment is a temporary effect on the synchronization of neuronal firing – it does not improve or increase brain functioning, it does not change the hardwiring, nor does it cure any neurological disorder. There is no compelling evidence for any effect beyond the period of entrainment itself.

However, very experienced practitioners of meditation are able to enter a Delta state and maintain consciousness at the same time. Yoga nidra or “yogi sleep” is a sleep-like state which yogis report during their meditations. This lucid sleeping state is among the deepest possible states of relaxation while still maintaining full consciousness (“super-conscious mind”). In this state, experienced yogis are able to regulate their body temperature and heart rate.

Think about it for a moment...your mind is at work all day, every day. Every decision you make, every challenge that you face, every moment you go through in life, your mind is your constant companion, and it can be your best friend or your worst enemy. Your mind is something you need to take good care of, because your quality of life is directly related to your "quality of mind".

Other entrainment methods sometimes used include autopan modulation that moves sound in an 180º arc to create a desired tone. Harmonic box entrainment, invented by James Mann, uses a layering of binaural and monaural tones that alternate between ears, requiring headphones. Sound modulation and filtering, amplitude modulation, and pitch panning use diverse sounds to create rhythmic pulses matched to the desired brainwave frequency. 
Building on guided imagery, you can also imagine yourself achieving goals like becoming healthier and more relaxed, doing well at tasks, and handling conflict in better ways. Also, visualizing yourself doing well on tasks you’re trying to master actually functions like physical practice, so you can improve your performance through ​​visualizations as well.
One of my habitual ways to unwind, get into an easy meditative state, and let the stress of the day melt away is by listening to binaural beats from these guys. So please do try them out! Their work is of the highest quality. (Note: yes, our website does earn affiliate commissions from them, but I only recommend them because I personally use their music to help relax my mind and reduce nervous tension – and it works!)
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.
The mechanism for this is that when your eyes or ears are exposed to a particular frequency of pulses or beats, the thalamus first distributes this information to the entire brain, including the visual and cerebral cortex where neural activity begins to synchronize to the incoming frequency, producing hemispheric synchronization and a balance of brainwave activity across the brain.
Hi Jason, thanks for all the uploads to youtube. I’ve been using them in work recently to help me concentrate and relax. I like the music tracks that you’ve chosen to overlay the tones. A couple of times in the last 2 weeks I’ve experienced the wavy pulse like sound, similar to the tones in my left ear. I wasn’t listening to tracks at the time or that day. It doesn’t last but it feels a bit strange. I wondered if I might have been listening to the tracks too loudly and that it was almost like a type of tinnitus. I’m curious to know if anyone has been in touch with you in the past to say they’ve had a similar experience?
^ Trost W. and Vuilleumier P., Rhythmic entrainment as a mechanism for emotion induction by music: a neurophysiological perspective. In The Emotional Power of Music: Multidisciplinary Perspectives on Musical Arousal, Expression, and Social Control, Cochrane T., Fantini B., and Scherer K. R., (Eds.), Oxford, UK: Oxford University Press; 2013, pp213–225.