Specific tones that resonate at certain frequencies are created and embedded within the acoustic architecture of the original waveform. Your brainwaves latch onto these embedded carrier frequencies and attune themselves to the same vibratory rate. Brainwave entrainment now occurs that is similar to binaural beats yet there is no need for headphones to deliver these entrainment effects.
Meditation enhancement: There are several companies that sell brainwave entrainment sessions specifically designed to enhance meditation. The sounds provide a stimuli to focus on during the meditation, and the brain waves naturally shift towards the frequency provided. Whether meditation is actually enhanced by brainwave entrainment is a subject of debate. However, advanced meditators commonly experience brainwave synchronization – which the right and left hemispheres display the same frequency brain waves.  While there are scientific benefits of meditation, it is unclear as to whether they are enhanced, hindered, or unaffected by adjunctive brainwave entrainment.
Insomnia and PTSD for most of my life are real bears that I wrestle with every night. A brain neural-therapist (for lack of a better description) said that this kind of sound recording may help. It is not music. When I remember to play the disc, I fall asleep within the first 5-8 minutes. One day I played the disc while cleaning and I was very surprised to hear how much of the recording I never recall hearing before. That's why I know how long it takes to fall asleep.
Brainwaves, or neural oscillations, share the fundamental constituents with acoustic and optical waves, including frequency, amplitude and periodicity. Consequently, Huygens' discovery precipitated inquiry[citation needed] into whether or not the synchronous electrical activity of cortical neural ensembles might not only alter in response to external acoustic or optical stimuli but also entrain or synchronize their frequency to that of a specific stimulus.[16][17][18][19]

Both brainwave entrainment and neurofeedback deal with brainwaves, but the similarity stops there. Entrainment pushes your whole brain into a pre-determined state, while neurofeedback teaches you how to move specific parts of your brain on your own. It is the differeence between forcing the brain into a given position, and skills building so you can move it there yourself.