Spectrogram Generator

The 'Spectrogram Generator' is an online audio visualization tool that uses the Web Audio API's AnalyserNode and FFT (Fast Fourier Transform) to render the frequency spectrum of an audio file over time. A spectrogram is a graph where the horizontal axis represents time, the vertical axis represents frequency, and color intensity represents amplitude, helping you inspect how frequency components change.

The tool supports MP3, WAV, M4A, OGG, WebM, and other formats that your browser's AudioContext can decode. Four color maps are included: Inferno, Viridis, Grayscale, and Hot. They are browser-friendly approximations for visual inspection rather than exact scientific color reproduction. Use them to inspect attacks, noise bands, vowels and consonants, harmonics, environmental sound patterns, or any audio feature you want to save as an image.

By switching the FFT size across five levels from 256 to 4096, you can adjust the trade-off between time resolution and frequency resolution. Smaller FFT sizes show short events more clearly, while larger FFT sizes show finer frequency differences. Minimum and maximum decibel sliders help hide background noise or emphasize quieter details.

Related Tools Use the [Audio Pitch Detector](/en/audio/audio-pitch-detector/) when you need note names and frequency values, or the [Music Key Detector](/en/audio/music-key-detector/) when you need the key of a full song. Use the [BPM Counter](/en/audio/bpm-counter/) for tempo checks. Before analysis, [Audio Normalizer](/en/audio/audio-normalizer/) and [Audio Noise Reducer](/en/audio/audio-noise-reducer/) can make the sound easier to inspect. To compare the result after changing pitch or tempo, use the [Audio Time Stretch Tool](/en/audio/audio-time-stretch/).

All processing is performed in your browser, and audio data is not sent to a server.