The History of Sound at the Monroe Institute

Since the earliest days of the Monroe Institute, sound has played a principal role in helping people reach and explore the powerful states of expanded awareness that Robert A. Monroe mapped and wrote about in his books, Journeys Out of the Body, Far Journeys and Ultimate Journey.

Our relationship with sound grew out of Bob’s professional career in radio broadcasting and his research on how to use specific sound patterns to facilitate sleep learning. Early on in this research, Bob and his team identified binaural beats as a promising technology to induce beneficial states of expanded awareness. This discovery shifted their focus from sleep learning to the study of expanded states of consciousness. 

The Binaural Beat

A binaural beat is an auditory illusion, first discovered in the 19th century, that occurs when two tones of slightly different frequencies are played in each ear. To reconcile these two tones, the brain produces a third tone that sounds like a single pulsating beat. 

A binaural beat of 5 Hz, for example, will cause an increase in Theta brain-wave production in the listener, stimulating a meditative state of consciousness.

This pulsating effect creates a “frequency following response” in the brain waves of the listener—a phenomenon known as “brain-wave entrainment”—in which the listener’s brain waves synchronize with the pulsating frequency, creating a corresponding shift in consciousness. A binaural beat of 5 Hz, for example, will cause an increase in Theta brain-wave production in the listener, producing a meditative state of consciousness. This entrainment phenomenon is, in fact, not new at all, as cultures around the world have used drumming and resonance chanting for thousands of years in meditation and shamanic rituals to induce altered states of consciousness. 


… binaural beats encouraged both hemispheres of the brain to
work in unison to create a “whole brain” state, which Bob referred to as “hemispheric synchronization.”

What made binaural beats particularly interesting to Monroe’s research team was that in addition to creating a frequency following response, binaural beat frequencies encouraged both hemispheres (the left [logic] and right [creativity]) of the brain to work in unison, creating a “whole-brain” state that Bob referred to as “hemispheric synchronization.” This was thought to occur because both hemispheres of the brain had to work together to recognize the two independent tones as a single tone. 

Building on this basic technology, the research team at Monroe conducted extensive EEG studies while subjects listened to frequency blends that corresponded to the specific expanded states of consciousness that Bob and other research subjects experienced. Once mapped, the team created audio-supported meditation exercises that 

proved effective at encouraging the same brain-wave frequencies and specific states of expanded consciousness, by engineering complex layered combinations of binaural beats and other sound signals. To label these expanded states of awareness in scientific, non-dogmatic terms, Bob named them “focus levels,” for example Focus 15, a state of awareness where linear time is no longer experienced. He called the sound technology Hemi-Sync©.

Over the years, we have continued Bob’s work, mapping over a dozen additional Focus levels and creating specific sound mixes to help people experience these new Focus levels. With feedback from thousands of participants in our residential programs, these layered mixes are continually refined to be as engaging and  effective as possible. The timeline below shows the evolution of our sound technology, now called Monroe Sound Science.

Monroe Sound Science

Since the sale of Hemi-Sync, our sound technology research and development has taken place under the brand name Monroe Sound Science (MSS). It includes binaural beats plus many other types of sound technology (i.e. phase modulation) and focuses on two key areas of innovation.

The first area is related to the specific techniques used for brain-wave entrainment. With the incredible technology and software available today for audio production, much more sophisticated techniques are available. Several new brain-wave entrainment techniques, beyond the original binaural beat technology, have been developed and extensively studied by the research team at the Monroe Institute. These techniques are:

  • More nuanced for a smoother transition between Focus levels 
  • Able to overcome the limitations of binaural beats; specifically entraining high-frequency Gamma brain waves observed in highly advanced meditators and associated with peak experiences. 

The specific details of these entrainment techniques are confidential and only available in Monroe Sound Science offered by the Monroe Institute.

The second area is the active development and refinement of the layered signal mixes used to reach specific Focus levels (identified states of awareness). One of the biggest advancements in this respect is the addition of high frequency Gamma signals to the entrainment mixes, made possible by the new techniques employed in MSS. The Gamma brain-wave state allows the listener to maintain a much greater degree of conscious awareness during deeply profound states of expanded consciousness, for a heightened awareness of the experience and less drowsiness. In addition, Monroe’s research team is developing:

  • New entrainment mixes to reach states of awareness outside of the original “Focus levels,” like lucid dreaming and bilocation.
  • Added dimensions of time to create dynamic entrainment mixes that adapt over the duration of an exercise to better guide the listener through sequential states of awareness specific to the exercise’s purpose.

Our Philosophy 

We at the Monroe Institute believe there are many paths on the journey of self-discovery, and having more choices means that there are more opportunities for people to find a path that is perfectly suited to them. Some may find they prefer the classic binaural beats, while others may be drawn to the latest advancements in Monroe Sound Science.

Many of our virtual and residential programs at the Monroe Institute still use the classic Hemispheric Synchronization technology originally developed by Bob Monroe himself. We encourage our participants to use the best tools and resources available to them on their journey of self-discovery.

Monroe Sound Science meditation exercises are available for purchase under various CD and digital download titles in our online store at and featured exclusively in our new mobile app “Expand: Beyond Meditation,” available for free in the Apple and Google Play app stores.