I have been creating all sorts of audio for meditation, relaxation, self programming, ultrasonic subliminal messages etc for half my life when releasing this website. Some may know me as the guy behind BlissCoded sound.  I have over 9 million views on my BlissCoded sound videos on youtube. It is incredibly popular and obviously something people really love. BrainAscend is my gift to you. Feel free to visit me over at www.blisscodedsound.com and discover an amazing sound technology I discovered/invented using the Golden ratio principle, which you can try for free.

Isochronic tones work just the same in delta as they do in alpha, theta and beta and they are widely used in the brainwave entrainment community to help people sleep. Like you, I’ve also seen some websites saying they don’t work in delta, but it’s a bit like the game of Chinese Whispers, where someone makes a comment and then after it gets passed around and shared a lot the message gets distorted and appears to be a fact. I don’t know of any scientific reason why they wouldn’t work in delta. I remember some people talking about this on a brainwave entrainment forum many years ago. They were saying they found isochronic tones a bit too abrupt for using to help them sleep and they preferred binaural beats, as they thought they were a more soothing sound. That was just a personal preference shared by a couple of prominent forum members at the time and some people then took that as a fact for everyone. That’s where I think that belief originated from.
The eyes of the participants were closed and the VFP goggles illuminated in alternative manner; first the right eye, then the left. The rate at which the photic stimulation was conducted ranged between 0.5 Hz and 50 Hz. Of the 50 patients with migraines, 49 considered their headache as having been “helped” by the stimulation and 36 noted that their headache had completely “stopped” from the VFP goggles.
3) Theta waves – these waves exist between 4 and 7 Hz. This state is commonly referred to as the dream or “twilight” state. Theta is associated with learning, memory, REM sleep and dreaming. Memory development is also enhanced while in this state. When in a theta brainwave state, memory is improved (especially long-term memory), and access to unconscious material, insights and creative ideas is increased.
While originally brainwave entrainment was achieved by using pure tones of sound, it is now possible to take these tones and blend them with music, rhythms, and natural sounds, such as the sounds of flowing water, bird sounds, or waves lapping on a beach, creating extended tracts of varied and intriguing brainwave entrainment music for everyday use.
One can also learn to control and slow down their brain waves through various neurofeedback technologies such as electroencephalograph (EEG), galvanic skin response (GSR), and heart, pulse and breath rate monitors. These devices measure stress and relaxation parameters and then "play" back the signals to the user so they can use the signals as a beacon to guide and "steer" themselves into a relaxed state. This takes some time, work and discipline but is much quicker than learning meditation.
The formal name for this process is called the “frequency following response”, where the human brain will literally “follow” a specific frequency/beat after being exposed to it for (usually) about 8 minutes.  Technically the definitive term “entrainment” does not exactly match the actual process of what is happening to your brain when listening to these audios, but its close enough, and the name has stuck now with these products becoming more popular and widely known.
They use a proprietary process of ‘3 point dynamic audio entrainment’ which means that they use both binaural beats and isochronic tones, layered together with another process called temporal entrainment (the stretching and compressing of sound waves in order to speed up or slow down the brain). This 3 pronged effect on your brainwaves is very powerful, so powerful they are currently in the process of trying to patent it.
Because the brain filters and interprets reality in a split-brained way, we tend to see things as separate and opposed, rather than as connected and part of the oneness spoken of by the great spiritual teachers (and, in the last few decades, by quantum mechanical physicists). Thus, at a deep level, the dual structure of our brain, in conjunction with brain lateralization, predisposes us to see and experience ourselves as separate from, and often in opposition to, the rest of the world—instead of experiencing the elegant interconnectedness between us and everything else. Our childhood associations and programming build on this inborn tendency by training us to seek this and avoid that, to move toward pleasure and away from pain, to do good and not bad, and so on. The greater the lateralization in the brain, the greater the feelings of separation—and the greater the feelings of separation, the greater the fear, stress, anxiety, and isolation.
My personal experience of this was that it could get very harrowing; at times, I would literally be gritting my teeth and contracting my ribs while I was in meditation, because it was pushing me so hard. I began to ask, “Is it necessary to push this hard in such a static way and create overwhelm over such prolonged periods in order to propel spiritual evolution?”
My final point is that brainwave entrainment is worth trying, and instead of being stopped by the fear of its improper use, you better reap its numerous benefits by following the safety guidelines I went through in this article. So, it all comes down to the question – are you ready to take your ability to create what you want for yourself in life to the next level?
Initially the children were entrained to a mu-alpha rhythm (7 to 9 Hz) to decrease theta waves. After the initial mu-rhythm entrainment, they entrained SMR-beta waves for 22 minute sessions. The results as interpreted by TOVA demonstrated significant improvements in: inattentiveness, impulsivity, and variability. Teachers and parents also reported behavioral improvements among the children. Using the right brainwave entrainment protocol may be a potential Adderall alternative for those with attentional deficits.
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.

Neural oscillations are rhythmic or repetitive electrochemical activity in the brain and central nervous system. Such oscillations can be characterized by their frequency, amplitude and phase. Neural tissue can generate oscillatory activity driven by mechanisms within individual neurons, as well as by interactions between them. They may also adjust frequency to synchronize with the periodic vibration of external acoustic or visual stimuli.[3]