Binaural Tones: at the Intersection of Sound and Neuroscience

When we listen to music, we experience more than just the melody or rhythm. What the human ear hears is a complex web of sound, woven together by a series of hidden vibrations that our ears may not always consciously notice but are crucial to shaping the way we perceive sound. This web of frequencies is made up of the fundamental tone and a series of overtones and harmonics.

Every note that the ear receives is a combination of many different frequencies. For example, when a double bass plays a low E at about 41 Hz, that’s the fundamental frequency. At the same time, the bass creates additional vibrations—harmonics—that are whole-number multiples of the fundamental frequency: 82 Hz, 123 Hz, and so on. These harmonics are present in every sound we hear, even if we’re not consciously aware of them. They add richness and color to the sound, turning a simple note into something far more complex and textured.

The intersection of auditory perception, brainwave modulation, and physiological synchrony presents an exciting frontier for advancing both neuroscience and holistic well-being. I am honored to be part of a team that researches tools to enhance the synchronization between neural oscillations and the frequencies of other bodily organs. Binaural tones, also known as binaural “beats”, are a type of sound therapy created by presenting two slightly different auditory frequencies to each ear, have the potential to influence brainwave activity and facilitate synchronization between the brainwaves and organ frequencies. Our research explores the possibility that this synchronization can promote emotional and psychological well-being and even foster a deeper connection between human beings.

Despite the growing interest in binaural tones, there is a notable gap in empirical studies that investigate their physiological effects and their role in human interconnection. Current research on binaural tones has predominantly focused on their effects on brain activity but lacks a comprehensive understanding of how they synchronize neural rhythms with other bodily systems, such as the heart and gut. Our team addresses this research gap by applying rigorous scientific methods to explore the relationship between binaural tones, well-being, and human connection. We seek to offer binaural sound therapy as an accessible and affordable tool for improving mental and physical health, as well as fostering greater interpersonal connection.

We offer listeners the opportunity to experience the complexity of sound through looping. We bow the double bass, then loop this single note, and then layer a second bowed note that’s slightly dissonant relative to the first. When we listen to these frequencies together through headphones, our brains notice that they begin to interfere with each other, creating a phenomenon known as beating.

With headphones on, my brain often starts to hear something other than the two notes that we play and loop. This phenomenon is called binaural perception. This is when each ear hears a slightly different pitch, the brain tries to make sense of it by generating a third tone that doesn’t actually exist in the sound. This is the basis of binaural tones.

For example, if one ear hears a sound at 100 Hz and the other hears 104 Hz, the brain doesn’t hear them as two distinct tones. Instead, it perceives the difference between them—4 Hz—as a kind of rhythmic pulsing or beat. These binaural beats are often used in relaxation or meditation music because they can influence brainwaves, encouraging various mental states. It’s as if the sound is inviting the brain to entrain itself to a different frequency, allowing for brain body shifts to occur.

The brain and body are naturally wired to respond to these frequencies.

The phenomenon of brainwave entrainment happens when external rhythms (like binaural beats) influence the natural electrical oscillations in your brain. For instance, frequencies in the Alpha range (8–12 Hz) are associated with a relaxed and alert state of mind, while Beta and Gamma waves are associated with performance, focus and complex task completion. Theta waves (4–8 Hz) are linked to deep relaxation and meditation, while Delta waves (1–4 Hz) are associated with deep sleep.

The human brain operates through electrical activity, producing oscillations or rhythms that help regulate everything from emotions to organ function. These brainwave frequencies govern states of consciousness, from relaxation to deep thought, to deep sleep. And just like a musical instrument, the brain can be tuned. However, all brains are different, and it’s important to remember that, for a person on the ASD spectrum, Gamma waves may be extremely dysregulating and make it harder to focus.

When we listen to a set of binaural tones, the external sound waves begin to influence the brain's natural rhythms.

For example, when listening to tones that allow the brain to produce a difference tone—what we call a third tone—of 10 Hz, the brain starts to synchronize with that rhythm, promoting a calm yet alert mental state. This process is called entrainment, and it’s the reason why certain sounds can help us relax, meditate, or even focus better.

Interestingly, these frequencies don't just stay in the brain. They have a direct effect on the body, influencing everything from heart rate to breathing. 10 Hz third tone, for example, sychronizes with the basal gastric rhythm, creating the slowest shared rhythm in the body, that between the gut and the brain. Neuroscientists such as Wolfgang Klimesch have proven that these shared frequencies have the capacity to couple and decouple at different times of day in order for the body to function optimally.

Conversely, each organ in the body vibrates at its own frequency. When neural oscillations and organs oscillations sync, there is a resting heart rate, a basal gastric rate, and other shared frequencies that control how our bodies function. Because our project offers acoustic dissonant tones to invite brain body syncing, the overtone series is also part of the experience of listening for some people. Even though we are still studying the implications of acoustic binaural tones that include the potential for the overtone series to be perceived, we have a lot to learn about what’s possible through this expansive experience.

It is no wonder that different cultures have used sound for its healing properties for centuries. Now, science is catching up with ancient practices, showing us just how deeply sound can support our bodies and minds in the process of restoring balance and finding well-being that is sourced from within.

References

CHOE, A.S., TANG, B. SMITH, K.R. et al. 2021. Phase-locking of resting-state brain networks with the gastric basal electrical rhythm. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0244756#abstract0

KLIMESCH, W. 2018. The frequency architecture of brain and brain body oscillations: an analysis. European Journal of Neuroscience, 2431-2453. doi: 10.1111/ejn.14192.

MAGSAMEN, SUSAN. Our Brains on Art: An Ancient Prescription for 21st Century Solutions. 2024. Journal of Neuroscience, 44 (44) e1833242024.

PRICE, C. J., THOMPSON, E. A. & CHENG, S. C. 2017. Scale of Body Connection: A multi sample construct validation study. PLoS One, 12, e0184757.

RICHTER, C. G., BABO-REBELO, M., SCHWARTZ, D. & TALLON-BAUDRY, C. 2017. Phase-amplitude coupling at the organism level: The amplitude of spontaneous alpha rhythm fluctuations varies with the phase of the infra-slow gastric basal rhythm. NeuroImage, 146, 951-958.

TIRDAD, S. A., AHMADI-PAJOUH, M., NASRABADI, A. M. 2018. Cumulative effects of theta binaural beats on brain power and functional connectivity. Biomedical Signal Processing and Control, Volume 42, 242-252.

YOUNG, A. HUNT, T. & ERICSON, M. 2022. The Slowest Shared Resonance: A Review of Electromagnetic Field Oscillations Between Central and Peripheral Nervous Systems. Frontiers in Human Neuroscience, Sec. Cognitive Neuroscience, Volume 15 – 2021.