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.
First of all, thank you for a most remarkable achievement. I have tried products in the past that purported to synchronize meditation-level brain waves — usually overlain by sappy new-age music composed by non-composers — and was invariably disappointed. However, I have been using your Equisync II and Equisync III recordings for a few weeks now and the results are truly astonishing and live up to the claims on your website.
Recently developed entrainment software has been designed to correct specific imbalances in hemispheric activity associated with undesirable mind-states. For example, people suffering with depression often have more activity in the right hemisphere, and specially designed brainwave music decreases this activity while increasing activity in the left hemisphere, reducing depression.