This audio combines relaxing music with isochronic tones to help assist with sleep induction. The isochronic pulses commence at 14hz Beta, which corresponds to a fully conscious state of awareness. However they immediately descend down through Theta, culminating with Delta at the 30-minute mark, which plays out the remainder of the track. The slow rate at which the brainwave entrainment frequencies descend can have a very relaxing and hypnotic effect on the mind; the alternative is to commence right away with the target Delta frequency, but I believe this method provides a more natural progression.
Headphones are optional for this session – for best results, listen at a comfortable, low volume where you can just about hear the low isochronic pulses.