Two tones, one beat
Play 200 Hz in your left ear and 206 Hz in your right. Neither ear hears a pulse, yet you perceive a soft beat six times per second. That beat is created in the brainstem, where signals from both ears first meet, not in the air. This is a binaural beat, first described in the 1830s and popularised by Gerald Oster in 1973. Established
Because the beat only exists when each ear gets its own tone, it needs headphones. Through a speaker the two tones mix in the room and you just hear a plain tone.
Does it change your brainwaves?
The Gateway report argues that the beat pulls both hemispheres to the same frequency, "hemispheric synchronisation". The modern name for the broader idea is entrainment: brain rhythms following an external rhythm.
The evidence is mixed. A 2023 systematic review of 14 EEG studies found five results consistent with entrainment, eight that contradicted it, and one mixed. Methods varied so much that the authors could not draw a firm conclusion. Emerging
Does it help you relax or focus?
On felt outcomes the picture is more encouraging. A 2019 meta-analysis of 22 studies found binaural beats had a small-to-moderate effect on anxiety, attention and pain perception, with effects larger when people listened for a while before a task. Effects vary a lot from person to person. Emerging
If you dislike the tone
You can lower it or turn it off in the player's Mix settings. The voice, the relaxation and the rehearsal still work; you lose only whatever the beat itself adds, which for some people is little.
Sources
- Oster, G. (1973). Auditory beats in the brain. Scientific American, 229(4), 94-102. doi:10.1038/scientificamerican1073-94
- Ingendoh, R. M., Posny, E. S., & Heine, A. (2023). Binaural beats to entrain the brain? A systematic review of the effects of binaural beat stimulation on brain oscillatory activity, and the implications for psychological research and intervention. PLoS ONE, 18(5), e0286023. doi:10.1371/journal.pone.0286023
- Garcia-Argibay, M., Santed, M. A., & Reales, J. M. (2019). Efficacy of binaural auditory beats in cognition, anxiety, and pain perception: a meta-analysis. Psychological Research, 83(2), 357-372. doi:10.1007/s00426-018-1066-8
- Chaieb, L., Wilpert, E. C., Reber, T. P., & Fell, J. (2015). Auditory beat stimulation and its effects on cognition and mood states. Frontiers in Psychiatry, 6, 70. doi:10.3389/fpsyt.2015.00070