See which frequencies a sound is made of.
Turn on the microphone and the sound it hears is split into frequencies at once: a live spectrum, a spectrogram of the last 10 seconds and octave bands. The strongest frequency is shown with its note and cents, alongside prominent peaks and mains hum. Sound is analysed in memory on this device; it is never recorded.
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Key features
- Live spectrum
- A line or bar curve on a logarithmic or linear frequency axis. The cursor reads the frequency, note and level at any point; Space freezes and resumes the view.
- Spectrogram and octave bands
- The spectrogram shows the last 10 seconds (now at the top, 10 seconds ago at the bottom). The octave view is drawn in 1, 1/3 or 1/6 octave bands (IEC 61260-1).
- Strongest frequency and note
- The strongest frequency is found with parabolic interpolation and shown with its note (C D E or Do Re Mi), cents and level; the A4 reference is adjustable. Prominent peaks are listed, and 50 and 60 Hz mains hum is marked separately.
- Measurement settings
- Averaging (off, low, medium, high), peak hold (2 s, 5 s, infinite), Z / A / C weighting (IEC 61672-1), frequency range (all, speech, bass or custom), resolution (FFT 4096 / 8192 / 16384) and window (Hann, Blackman, flat top).
- Snapshots and comparison
- "Take snapshot" saves the current spectrum. When two or more snapshots are selected, their curves are drawn over the live spectrum and the frequency of the largest difference is shown; for example, a speaker's curve before and after correction.
- Audio file analysis
- Audio files the browser can decode (WAV, MP3, M4A, OGG, FLAC …) are opened on the device; the moment being played or the whole file is analysed. There is playback and a position bar; the file is never uploaded.
Data processing and privacy
Hertzio listens to the microphone only when you turn it on, and turns it off when the app goes to the background. Sound is analysed in real time, in memory on this device; it is never recorded, stored or sent anywhere. Audio files are opened on the device too. Snapshots and settings are kept on this device (in the browser's IndexedDB storage).
Get Hertzio
Try it in the browser without installation; for continued use, purchase the version for macOS, Windows or Linux.