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. 

Headaches: There are several reports of brainwave entrainment providing therapeutic benefit for those suffering from general headaches or migraines. A study in 1985 analyzed photic stimulation within the theta range (5 Hz to 8 Hz) and discovered that this protocol provided significant headache relief. A total of 19/24 participants noted that the “slow wave” photic stimulation provided “complete relief” from chronic headaches and migraines.
All brainwave states serve important mental functions, and with today’s lifestyle, returning to a peaceful way of being is becoming increasingly difficult to achieve and maintain for any period of time. This continual stress or alerted state causes disease in the mind and body, which is why it’s paramount for us to relearn or retrain ourselves to get back to these healthful and rejuvenating states.
I have personally used Holosync, Neuroprogrammer 3, and now I'm currently using Brain Evolution System. They are all great programs within their own rights. Holosync is very pricey and takes many years to complete (6-10 yrs) for their 12 level program and has a hefty price tag of $3195 dollars for the complete set and it uses outdated binaural technology. Neuroprogrammer 3 doesn't have a set time limit for completion as you set your own pace and use whatever sessions you choose to use and you can get the ultimate version for under $100, but this isn't a program that you would use daily in most cases. It does use better technology ( binaural & isochronic ) but it more suited for specialized cases and can be used in conjunction with Holosync or BrainEv. I have just started using BrainEv and I am about to be into the second week. BrainEv uses state of the art binaural and isochronic technology and brings you through your states at a much rapid rate whereas Holosync focuses mainly on certain brain wave patterns during its sessions which could get your mind stuck in certain states because the brain gets used to the specific states it's been entrained to. Also, BrainEv takes just 6 months to complete and you can feel it working immediately. Holosync did do it's job but BrainEv takes the cake on this one due to the short duration of time it takes to complete and uses more advanced entrainment techniques that doesnt leave your mind in a static state. So I would difinately suggest using BrainEv ( first month is free; $299 for all 6 sets ) in conjunction with Neuroprogrammer 3 for more specialized brain training.
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.

Entrainment is a phenomenon seen is a wide variety of different natural circumstance. In the field of chronobiology, the study of biological rhythms in living organisms, entrainment is the synchronization of a circadian rhythm with the rhythm of an external pattern, such as the synchronizing of women’s menstrual cycles with the phases of the moon or with one another in a group.

Let's check in with another expert, chemistry professor Thomas Taylor from the Texas A&M. Taylor hooked a load of students up to an EEG machine (like you see in the movies with the sticky plastic pads with wires stuck all over people's heads) in an attempt to analyse 'synthesis thinking' - which is basically a nerd's way of saying "find out how people come up with new and creative ways to solve a problem".
Slower still are theta waves. Theta is best known as the brain wave state of dreaming sleep, but it is also associated with a number of other beneficial states, including increased creativity, some kinds of superlearning, increased memory abilities, visionary experiences, and what are called integrative experiences (where we make broadly-based positive changes in the way we see ourselves, others, or certain life situations).
You also may find that after pushing yourself really hard, now you have pushed yourself a little too much, and you’re getting into overwhelm. You may want to ride that overwhelm like a wave to where it’s pushing you just a little bit, but not so much that it will push you over the edge and have you take a dive. So, maybe on Saturday, after pushing hard all week, you might decide to put on the releasing tracks. In this way, you can still experience a very deep and blissful meditation, but without all the push from the carrier frequencies and the biofield amplitude.
Unlike many traditional therapies for dealing with stress, anxiety, depression or cognitive impairment, entrainment does not require a focused effort from the person having the therapy, as the brain instinctively follows the frequency. This makes it a much more effective therapy for managing some of these challenging conditions, by automatically inducing a sense of relaxation and a reduction in negative physical and emotional patterns.

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.

Behavior problems: In two separate studies with a total of 57 children, it was found that brainwave entrainment was able to significantly improve behavior problems. One of these studies was conducted on children with ADHD and determined that they significantly improved not only in regards to attention deficits, but also in their behavior. Both parents and teachers reported statistically significant improvements in how the children behaved.
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]