The 9 Solfeggio Frequencies — 174 Hz to 963 Hz
Each frequency in the solfeggio scale has a distinct acoustic character and practical application. This is the reference page — acoustic properties, research basis, and use case for each one.
Sub-bass grounding. Physical tension, sleep onset, somatic anxiety.
Gentle low-mid. Rest and recovery sessions.
Warm mid-low. Anxiety, fear, morning grounding. Best starting frequency.
Forward mid. Clearing, transitions, morning sessions.
Clear mid. The most researched frequency — documented cortisol reduction. Focus and clarity.
Rich upper-mid. Openness, creativity, receptivity.
Bright upper-mid. Daytime alertness and discernment.
High range. Open awareness meditation and insight.
Highest in the scale. Short sessions only. Most activating.
All 9 frequencies — free in the app
Solfeggio Sanctuary generates all frequencies from 174 Hz to 963 Hz with pure tones and tuning forks. Free download. Pro adds crystal and Tibetan bowls for €4.89 once.
How solfeggio frequencies work
Solfeggio frequencies are specific acoustic tones that influence the autonomic nervous system through the frequency-following response (FFR): the brain's tendency to synchronise its neural oscillations with a sustained external acoustic stimulus. Unlike binaural beats, solfeggio frequencies do not require headphones — they work through any speaker.
The most directly evidenced effect is cortisol reduction: Akimoto et al. (2018) found measurable cortisol reduction in human subjects after five minutes of 528 Hz exposure. The general autonomic regulation effects are consistent with the frequency-following response mechanism documented by Hink et al. (1980) and Kraus & Nicol (2005).
For the full analysis of what the research supports and what it does not, see Do Solfeggio Frequencies Actually Work?