I've always been curious exactly where the rushing sounds came from. The theory behind this song is that there are two kinds of ions, negative ions that come from electrical appliances and positive ones that come from more natural areas such as waterfalls. I take it that the rushing sound is a positive ion and the electrical zap is a negative one. Keeping that in mind, I always thought it was intriguing how the negative ions start on the left and travel to the right, then (almost literally) snap back to the left again; whereas the positive ions stay mostly in the middle. The zap sound is always the same; same volume, same pitch, same decay. On the other hand, the positive ions are much more chaotic, swelling and always changing in volume and moving at a faster rate--there's one part near the end where it seems like the rushing sound is almost desperately raging. But for all that, the song ends with the negative ions, as the positive ions fade out into silence.
"Remember that feeling you've experienced near a waterfall or high in the mountains? Those are two places that thousands of negative ions occur. They create an effect on human biochemistry."
Not sure how accurate this information is since they are selling a product, but i thought i would share anyways.
I also read in a Feng Shui book that positive ions come from electrical appliances and are bad for the chi flow.
So maybe it's
(+) electrical, like zaps
(-) natural, like thunderstorms!