One second. A number of cycles.
Hertz (Hz) means cycles per second. A 200 Hz audio tone oscillates 200 times per second. In a binaural-beat example, a 200 Hz tone in one ear and 210 Hz in the other have a 10 Hz difference. That difference is not the same as the pitch of either tone.
EEG also uses Hz to describe rhythms recorded from the brain. Sharing a frequency label does not mean a sound automatically produces that brain state.
Delta · 0.5–4 Hz
A slow EEG band often associated with deep sleep.
Theta · 4–8 Hz
A band studied in contexts including drowsiness, memory, and meditation.
Alpha · 8–13 Hz
Commonly associated with relaxed wakefulness, particularly with eyes closed.
Beta · 13–30 Hz
A broad band discussed in relation to active thinking and attention.
Band boundaries vary slightly between sources. These are educational reference ranges, not prescriptions.
Choose a session first.
In the HFH app, start with a named experience: Focus, Calm, Sleep, or a generated meditation. The Frequency Generator provides a way to explore tones; always check whether a control represents an audible tone or a binaural-beat difference.
There is no universal optimal Hz setting for focus, calm, or rest. The research is mixed, and response depends on the person, stimulus, and listening context. Much of the published work uses conventional air-conduction headphones; it does not establish equivalent outcomes for HFH’s bone-conduction delivery.
Explore the HFH app ↗Read the research
Ingendoh et al., PLOS ONE (2023) reviews the inconsistent evidence for binaural-beat brainwave entrainment.
Beauchene et al. (2016) tested 5, 10, and 15 Hz binaural beats during a visuospatial working-memory task. A study setting is not an established optimal setting for everyday use.
