for activation perhaps.
When placed on an IBVA it is shown that the brainwave pattern of the photoreader is high theta and low beta with a distinct absence of alpha waves. So during the photoreading phase you'd be interferring with the photoreading process if your mind allows itself to be entrained by the CD.
Fortunately like I said the brain knows the correct pattern and will ignore outside interference in most cases. It may just make it more difficult for the beginner to find the right pattern by trying to rely on false entrainment.
Alex
