AUDIO · FREE TOOL
Audio spectrum explorer
Explore frequencies in a local PCM WAV, one window at a time.
Mono/stereo, little-endian 16-bit PCM WAV. Up to 25 MiB and two minutes; 8–192 kHz. MP3, AAC, compressed/float/extensible WAV are not supported.
Playback is optional and never automatic. Pause the player before choosing an analysis time; the chart analyzes your selected window, not live playback.
See the preview ↓Choose a sample or enter your settings to begin.
Data & measurements
Scroll sideways to see every column. You can also focus the table and use the arrow keys.
Read frequency without guessing loudness.
The spectrum shows a one-sided FFT with a periodic Hann window and coherent-gain amplitude correction. Frequencies are spaced at sample rate ÷ FFT size. For example, 48 kHz / 4,096 gives 11.719 Hz bins across an 85.333 ms window. The reported peak is a bin center, not an exact musical pitch. The plot floor is −120 dBFS; numerical results extend to −140 dBFS. Short final windows are zero-padded and labelled.
The waveform shows min/max samples in 600 time buckets. Left and right remain separate options; Mid averages them and can cancel opposite-polarity channels. Digital dBFS here describes windowed sinusoidal amplitude relative to a full-scale sine, not acoustic dB SPL, integrated loudness, hearing health or a calibrated measurement. Window choice, leakage and recording quality affect interpretation.
Analysis runs in a local worker. A selected PCM WAV is parsed before expensive processing; no microphone permission or upload is needed. Keep playback volume low when using the sample. References: periodic Hann window and Web Audio frequency-analysis terminology. Toolfred uses Hann rather than the AnalyserNode Blackman window. The FFT and illustration are original Toolfred code; no external DSP package is downloaded.