Reference
Frequency & Sound Therapy Glossary
Plain-English definitions for the terms you'll hear inside the hub — and honest citations to where the science actually lives. Skip the mysticism; keep what's real.
Solfeggio frequencies
A set of six (sometimes nine) tones — 396, 417, 528, 639, 741 and 852 Hz — popularised as an ancient tuning system.
The Solfeggio set was reintroduced in the 1970s by Dr Joseph Puleo, who linked them to a medieval hymn to St John the Baptist. There is no archaeological evidence that these exact pitches were used in ancient chant, but small modern studies show sustained tones in this range can lower cortisol and reduce anxiety. Treat the frequencies as a structured focus for calming sound — not a mystical code.
528 Hz
The "love frequency" or "miracle tone" — the third note of the Solfeggio set.
528 Hz has been tested in a small number of peer-reviewed studies. Findings that keep appearing: reduced salivary cortisol after ~5 minutes of exposure, lowered anxiety scores, and anti-oxidative effects on cell cultures compared with control frequencies. It will not repair DNA or cure disease — those claims are from popular books, not laboratories.
The 7 healing frequencies
396, 417, 528, 639, 741, 852 and 963 Hz — the extended Solfeggio set.
Each is associated with an intention: 396 (grounding/release), 417 (change), 528 (repair/love), 639 (relationships), 741 (expression/detox), 852 (intuition) and 963 (unity/awareness). The labels are scaffolding, not medicine. What is reliably measurable is that sustained pleasant tones in a safe environment shift the autonomic nervous system toward parasympathetic (rest) state.
Binaural beats
An auditory illusion created when each ear hears a slightly different frequency.
If the left ear hears 200 Hz and the right ear 210 Hz, the brain perceives a 10 Hz beat. Different beat frequencies are marketed for focus (beta, 13–30 Hz), relaxation (alpha, 8–12 Hz), meditation (theta, 4–7 Hz) or sleep (delta, 0.5–4 Hz). Meta-analyses show small but real effects on anxiety and mood; effects on memory and cognition are inconsistent.
Vibro-acoustic therapy
Low-frequency sound delivered through the body as vibration, not just the ears.
Typically 30–120 Hz sine waves transmitted through a mat, chair or wearable (e.g. Woojer). Reviewed for use in pain, Parkinson's tremor, fibromyalgia and general relaxation. The mechanism is a mix of mechanical stimulation of mechanoreceptors and entrainment of autonomic rhythms.
Schumann resonance
The Earth's natural electromagnetic frequency, ~7.83 Hz.
A standing electromagnetic wave in the cavity between the Earth's surface and the ionosphere. Sits in the human alpha brainwave range, which is why devices like PEMF mats often include a 7.83 Hz setting. Evidence for direct health effects of ambient Schumann exposure is weak; evidence for 7.83 Hz PEMF as a relaxation tool is moderate.
PEMF (Pulsed Electromagnetic Field therapy)
Low-intensity magnetic pulses delivered through a mat, coil, ring or wearable.
FDA-cleared for non-union bone fractures since 1979 and studied for pain, depression and post-surgical recovery. Frequencies are usually 1–100 Hz to overlap with human brainwave bands. Not the same as ionising radiation and not the same as EMF from phones or wifi.
Brainwave entrainment
Using rhythmic sound, light or vibration to nudge the brain toward a target EEG state.
Umbrella term covering binaural beats, isochronic tones, monaural beats and flicker light therapy. A 2008 systematic review found consistent effects on stress, pain and cognition — small but reproducible. The strongest evidence is for anxiety reduction.
432 Hz
An alternative concert-pitch tuning (A = 432 Hz) instead of the modern A = 440 Hz standard.
Popular in spiritual and alternative music communities. One small crossover study (Calamassi et al., 2019) found 432 Hz music produced slightly lower heart rate and blood pressure than 440 Hz music. Differences are subtle and the field is under-powered — pick the tuning your body prefers.
Sound bath
A guided session where you lie down and are immersed in sustained tones from bowls, gongs, tuning forks or synthesised frequencies.
A 2016 study of Tibetan singing bowl meditation showed significant reductions in tension, anger, fatigue and depressed mood, and increased spiritual well-being. Effect sizes were larger in participants new to the practice. Best treated as a nervous-system reset, not medical treatment.
HRV (Heart Rate Variability)
The variation in time between heartbeats — a proxy for autonomic nervous system balance.
Higher HRV generally indicates better recovery and parasympathetic tone; lower HRV correlates with stress and over-training. Sound therapy, breathwork and PEMF sessions are typically evaluated by pre/post HRV changes because it is an objective, minute-scale measurement.
Related reading
Educational reference only. Nothing on this page is medical advice or a substitute for care from a qualified clinician. Speak to your doctor before starting any new wellness protocol, especially if you are pregnant, have a pacemaker or implanted device, or an active seizure disorder.