Audio Frequency Analyzer

The Audio Frequency Analyzer is a dedicated online tool for real-time analysis and visualization of frequency spectrums from audio files and microphone input. Using the Web Audio API AnalyserNode, it decomposes audio signals into frequency components via FFT (Fast Fourier Transform) and displays them visually.

Choose from three visualization modes—bar graph, line curve, and circle radial—each offering unique perspectives on frequency characteristics. The bar graph mode provides intuitive frequency distribution visualization with gradient colors from low to high ranges. The line mode displays a smooth curve showing frequency characteristics, while the circle mode offers a unique radial display radiating from the center.

Flexible frequency scale selection (linear and logarithmic) allows analysis across the entire audio spectrum. With real-time peak frequency detection and musical note identification (C4, A4, etc.), this tool is ideal for instrument tuning, acoustic analysis, and sound design.

Voice pitch measurement is also supported. Speak into your microphone or play an audio file, and the tool detects your voice pitch (fundamental frequency, F0) in Hz using autocorrelation, displaying it with the musical note (e.g. A3) and Japanese karaoke-style vocal notation (e.g. hiA, mid2G#). Because the fundamental frequency is measured separately from the spectrum peak, the reading is robust against harmonics — you get an accurate answer to "how many hertz is my voice?"

The vocal range feature automatically records the lowest and highest detected pitches. Sing from your lowest to highest note and instantly see your vocal range (e.g. mid1C to hiA) — perfect for karaoke song selection and voice training logs. The range can be reset with one click.

The frequency axis now shows tick labels (100Hz, 1k, 10k, etc.), and hovering over the spectrum reads out the frequency at the cursor position. Analysis results can be saved as a PNG image for reports and sharing. Enhanced with 7 frequency band analysis (sub-bass, bass, low-mid, mid, high-mid, presence, brilliance) and loudness display in dB using RMS calculation. All processing occurs locally in your browser, and audio data is never sent to any server.