It seems that the effectiveness of creating some form of binaural beat technology was discovered on a practical level long before modern technology. The traditional Tibetan “Tingsha” cymbals or bells were slightly off pitch of one other to create form of sound wave prominent only when both bells sounded. These are commonly used in various meditation retreats announce the beginning of a meditative practice or to create a sacred space with sound.
As with many of these technologies, test the bells first to make sure they provide a relaxing and positive experience for you as an individual. They are a highly portable means of producing a clear sound that many find conducive to meditative practice.
Tibetan bowls also produce unique sound frequencies which may aid in reaching a deeply relaxed state. Some of these come in sets with tones specific to particular energies of the body.
Over the course of time, sometimes months to years, meditative practice allows the diligent student the ability to remain consciously aware at different rates of brainwave activity than that of waking state [beta]. It has also been observed that various types of drumming, from tribal to raves, provide a rapid access to trance states based upon the rhythm combined with overpowering volume of sound. In some manner these sounds alter brainwave state through a process usually referred to as entrainment. Once a particular brainwave state is achieved in this manner, it becomes easier to access the state without necessarily having to use the technology again.
For the individual wishing to experience a more solitary experience of binaural beats than tribal drumming, there are several options, ranging from CDs to light-sound machines. Robert Monroe studied the ability of sounds provided at slightly different pitches to cause an entrainment of brainwaves which related to the difference between the sound frequencies in each ear. This technology is designed to entrain brainwaves to more rapidly move into the frequencies often associated with meditative experience: low alpha to mid-theta. Most studies have suggested that people do not become reliant on these methods to reach meditative states. Rather, the technology can help them reach the states initially, but is not required to return to those same brain states in the future.
Interesting information from the journal Psychoneuroendocrinology regarding meditation and gene expression: