Singing Bowl Brainwave Entrainment: What the Evidence Shows

Introduction

Singing bowls produce complex acoustic signals. When two partials (overtones) are close in frequency, their interference creates amplitude modulation — a periodic "beating" at the difference frequency. For example, partials at 396 Hz and 402 Hz would produce a 6 Hz beat, placing it in the theta band (4–8 Hz). Choi & Jo (2023) measured a 6.68 Hz beat from a single bowl and observed increased low-frequency EEG power during exposure.

The question is whether this acoustic beating drives corresponding changes in brain oscillations, and if so, whether the relationship is specific to the beat's frequency band. This post summarizes what has been published on the topic and identifies where the evidence is insufficient.

The mechanism: monaural beats and frequency following

The proposed mechanism is the Frequency Following Response (FFR): neural oscillations synchronizing to periodic auditory stimulation. This is well-established in the auditory steady-state response (ASSR) literature for synthetic stimuli (Picton et al., 2003).

A distinction matters here. Singing bowl beats are monaural — the interfering partials are both physically present in the air and reach both ears simultaneously. This differs from binaural beats, where separate frequencies are delivered to each ear via headphones and the percept is constructed centrally in the superior olivary complex. Monaural beats produce physically measurable amplitude modulation in the acoustic signal itself. Schwarz & Taylor (2005) found that monaural beat ASSR had larger amplitude than binaural beat ASSR, consistent with stronger cortical response to physically present amplitude modulation.

What has been tested

Most singing bowl research measures psychological or physiological outcomes (mood, HRV) without characterizing the acoustic stimulus or recording EEG. Only three studies have measured EEG during or after singing bowl exposure, and only one analyzed the bowl's beat frequency:

Singing bowls and EEG

Choi & Jo (2023) provide the most direct test of the entrainment hypothesis. They recorded 2-channel EEG (F3/F4) from 17 participants during exposure to a single bowl with a measured 6.68 Hz theta-range beat frequency. They found delta power increased 135% and theta power increased 117% (p < .002), with spectral magnitude increases up to 251% at the beat frequency. The acoustic analysis was done offline in MATLAB (FFT + Hilbert transform), separate from the EEG recording.

Landry et al. (2018) tested two bowls (73 Hz and 110 Hz fundamentals) across 9 spatial projection conditions in 44 participants. They observed that the 73 Hz bowl produced gamma-range EEG changes while the 110 Hz bowl affected theta and beta bands. However, the study focused on spatial geometry, not acoustic characterization. No beat frequency analysis was conducted.

Walter & Hinterberger (2022) recorded 64-channel EEG during singing bowl massage in 34 participants. Overall EEG power decreased during sound exposure (d = −0.30, p = .002), with post-intervention decreases in beta2 (d = −0.15) and gamma (d = −0.21). Heart rate also decreased (p < .001). The study cannot separate auditory effects from tactile and vibratory stimulation because bowls were placed directly on the body. No acoustic characterization was performed.

Singing bowls without EEG

Trivedi & Saboo (2019) measured HRV in 33 participants comparing Himalayan singing bowls to supine silence. They found reduced stress index and increased HRV in the bowl condition. Goldsby et al. (2017) measured mood and tension in 62 participants before and after a sound meditation session, finding reductions in tension, anger, fatigue, and depressed mood (all p < .001). Neither study included EEG or characterized the acoustic properties of the bowls used.

Systematic reviews

Two recent systematic reviews cover the broader singing bowl literature:

Cai et al. (2025) reviewed 19 clinical studies (2008–2024) and found potential benefits for anxiety, depression, sleep, and cognition, but noted all 9 included RCTs had high risk of bias. Meta-analysis was not feasible due to heterogeneity across studies.

Lin, Yang & Wang (2025) reviewed 14 quantitative studies and reported that most showed reduced anxiety and depression, improved HRV, and decreased heart rate. EEG findings were inconsistent: decreased alpha and beta power was common, but delta and theta results varied across studies. Both reviews flag small sample sizes (12–81), inconsistent protocols, and absence of standardized acoustic characterization.

Binaural and monaural beat literature

The binaural beat entrainment literature provides relevant mechanistic context but is itself inconclusive. Ingendoh, Posny & Heine (2023) systematically reviewed 14 binaural beat + EEG studies: 5 supported entrainment, 8 did not, and 1 was mixed. They could not conduct a meta-analysis due to heterogeneity and concluded that the question cannot be settled at this point.

Engelbregt et al. (2021) tested binaural and monaural beats at 40 Hz in 25 participants (19 with usable EEG). The binaural condition reduced errors on an attention task (η²p = .142), while the monaural condition increased errors. EEG showed isolated electrode-level effects but no consistent entrainment at 40 Hz. Notably, 40 Hz is well above the frequency range of singing bowl beats (typically 1–13 Hz).

Alternative explanations

The existing data is also consistent with explanations other than frequency-specific entrainment. The EEG changes observed by Choi & Jo (increased delta and theta, decreased alpha, beta, and gamma) could reflect a general relaxation response to sustained tonal sound, attentional absorption by a novel or repetitive stimulus, or drowsiness onset during a passive listening task. No study has controlled for these alternatives — for example, by comparing bowls with different beat frequencies to test whether the EEG response varies by band, or by comparing bowl sound to a non-beating tonal control.

Open questions

Several questions have not been addressed in the published literature:

Is the EEG response band-specific? Only one study (Choi & Jo) analyzed the bowl's beat frequency and correlated it with EEG, and that study used a single bowl. Whether different beat frequencies produce changes in different EEG bands, or whether bowls generally shift activity toward slower oscillations regardless of beat frequency, is unknown.

What happens when acoustic and EEG data are synchronized? All existing studies either analyze audio separately from EEG or do not analyze the acoustic signal at all. Time-locked analysis of the beat envelope and the EEG response has not been done.

Does bowl construction matter? Hand-forged bowls produce complex inharmonic partials with rich beating patterns. Cast bowls have cleaner harmonic structure with less beating. The acoustic differences are confirmed (Terwagne & Bush, 2011), but whether they produce different neural responses has not been tested.

Do low-frequency monaural beats entrain? The binaural beat literature is mostly tested at 40 Hz (gamma range). Singing bowl beats operate at 1–13 Hz (delta through alpha). Monaural beats in this frequency range from a complex acoustic source have not been studied.

Does playing technique change the effect? Strike and rim play produce different spectral content and different beating patterns from the same bowl. This variable has not been characterized or correlated with EEG.

Summary

One study (Choi & Jo, 2023) found increased low-frequency EEG power during exposure to a bowl with a theta-range beat frequency. Whether this reflects frequency-specific entrainment, a general relaxation response, or something else cannot be determined from a single bowl and 17 participants. Two systematic reviews (Cai et al., 2025; Lin et al., 2025) find potential neurophysiological effects across the broader singing bowl literature but rate the evidence as low quality due to small samples, inconsistent protocols, and absent acoustic characterization.

The central unanswered question is whether the relationship between a bowl's beat frequency and the listener's EEG response is band-specific. Answering it requires testing multiple bowls with characterized beat frequencies across different EEG bands — something no published study has done.

References

Cai, X. et al. (2025). Therapeutic effects of singing bowls: A systematic review of clinical studies. Explore. PMC12063014
Choi, J. & Jo, S. (2023). Does the Sound of a Singing Bowl Synchronize Meditational Brainwaves in the Listeners? Int. J. Environ. Res. Public Health, 20(12), 6180. PMC10298245
Engelbregt, H. et al. (2021). Effects of binaural and monaural beat stimulation on attention and EEG. Exp. Brain Res., 239, 2781–2791. PMC8448709
Goldsby, T.L. et al. (2017). Effects of Singing Bowl Sound Meditation on Mood, Tension, and Well-being. J. Evid. Based Complementary Altern. Med., 22(3), 401–406. PMC5871151
Ingendoh, R.M., Posny, T.S. & Heine, A. (2023). Binaural beats to entrain the brain? A systematic review. PLOS ONE, 18(5). PMC10198548
Landry, M. et al. (2018). A Study on the Characteristics of an EEG Based on a Singing Bowl's Sound Frequency. Springer. doi
Lin, F.W., Yang, Y.H. & Wang, J.Y. (2025). Effects of Tibetan Singing Bowl Intervention on Psychological and Physiological Health in Adults. Healthcare, 13(16), 2002. PMC12385955
Picton, T.W. et al. (2003). Human auditory steady-state responses. Int. J. Audiol., 42(4), 177–219. PubMed
Schwarz, D.W.F. & Taylor, P. (2005). Human auditory steady state responses to binaural and monaural beats. Clin. Neurophysiol., 116(3), 658–668.
Terwagne, D. & Bush, J.W.M. (2011). Tibetan singing bowls. Nonlinearity, 24, C51–C66. PDF
Trivedi, S. & Saboo, N. (2019). A Comparative Study of the Impact of Himalayan Singing Bowls and Supine Silence on Stress Index and Heart Rate Variability. J. Behav. Ther. Ment. Health, 2(1). Link
Walter, S. & Hinterberger, T. (2022). Neurophysiological Effects of a Singing Bowl Massage. Medicina, 58(5), 594. PMC9144189