These are by far the most powerful and effective brain trainers. They work by utilising equal intensity tones and increasing the pulse speed to synchronise your brain with the rhythm. The more distinct and clear wave from harmonises your brain much faster. The effects can be felt without headphones, but using them will greatly enhance the effects.
This actually mimics the same methods used by the ancient tribesman who would beat their drums to a special rhythm. Trynaural Meditations are specially designed to produce exactly the right frequencies in your brain to produce the desired benefits.
The combination of isochronic tones with specially designed sounds and music is what creates the full effect of state change and stress reduction.