What's Brainwave Entrainment?

Brainwave Entrainment is the practice of using sounds, visual stimuli or even electromagnetic fields to alter the frequency of brainwaves.
It can be done for several reasons: people with insomnia can take great benefit from it, but it can also be used to improve your attention span, and even simulate the effects of some recreational drugs.
The effect is not in any way permanent, and usually fades away in less than a minute after the stimuli is removed.
Commonly used frequencies are: 10Hz (awake), 15-18Hz (focusing on something), 0.5-4Hz (deep sleep), etc. You can find more frequencies on the Internet.
Very rarely do these frequencies go beyond 20Hz. This application supports frequencies up to 40Hz.

Is it safe?

Brainwave Entrainment is perfectly safe, but if you suffer from epilepsy or a similar condition, you may want to consult your medic before trying it.

Does it actually work?

People react differently to Brainwave Entrainment: in general, it takes some practice before you can get the desired effect, and for ~15% of the population, it doesn't work at all.
If it's your first time using Brainwave Entrainment, you should start with something simple, like sleep-inducing presets, then you can move on to more complicated things like Astral Projections.

What are Isochronic tones?

Isochronic tones are a commonly used aural stimuli for Brainwave Entrainment. They consist of short pulses of (usually) a sine wave. These pulses can vary in frequency. Their frequency is called Entrainment Frequency, and is the frequency that you want to synchronize your brainwaves to.

Other types of aural stimuli are Binaural Beats and Monaural Beats. Isochronic tones are usually much more effective, and can be played through speakers, unlike Binaural Beats which require headphones.