Q: Why is rain the background for the music programs, individual and free?
A: I mention that with every system/product, yet will have to explain here as well. In short, it's to avoid your brain/mind to follow musical theme or melody instead of being here and now with consciousness directed/focused/concentrated to your inside.
Also, to avoid placebo effect as much as possible: how can one get anything special from the sounds of a natural raining (or similar, like ocean waves or rushing creek or pure white noise? Well, listen and experience for yourself.
Technically, the audible part (music/rain and thunder strikes mixed) is different in all three personalized growth systems, as is inaudible mental programming. With home study courses it is one rainy background and the difference is again only in this inaudible mental programming part.
I do not use any brain technologies like binaural beats, subliminal messages, etc. here. You can see how some of the leaders in that domain are doing it, for example Centerpointe and the Monroe Institute, to name a few without a special order.
This is done so in both free and paid versions, except paid one is specially energized and personalized for the known listener only.