saturalabs

Free tools for your next audio edit

Audio spectrogram. See how frequencies change over time.

Choose a short section of an MP3 or WAV and view its frequency content over time. Analyze one channel locally in your browser, without uploading audio or creating an account.

No account neededNo audio uploadWorks in your browser
Learn to read a spectrogram

View an audio spectrogram

Free · local

Analyze a section of up to 10 seconds. This visualization does not identify sources, remove noise or modify the recording. Audio stays in your browser.

Time, frequency and level

How to view an audio spectrogram

  1. 01 / FILE

    Choose a recording

    Open a supported mono or stereo MP3 or WAV up to 50 MiB and five minutes. The file is decoded locally at 48 kHz; browser decoding support varies.

  2. 02 / SECTION

    Select a moment

    Enter a start time and a duration up to 10 seconds. Choose left or right for a stereo file. Compare a quiet section with a noisy one using separate analyses.

  3. 03 / READ

    Inspect and listen

    Read time left to right and frequency bottom to top. Bright horizontal bands can reflect sustained tones; broadband vertical marks can reflect brief events. These are clues, not source identification.

Keep a visual reference

Save the spectrogram as a PNG image

After analyzing a section, choose Prepare labeled PNG, then Download labeled PNG. The static image includes frequency and time labels, the selected channel and the displayed color range. It is a picture of the analysis, not an audio file or an editable spectrogram. Choose another section and analyze again to create a separate image.

Understand the picture

What does this spectrogram show?

The chart uses overlapping 8,192-sample Hann-windowed FFT snapshots. Each column represents a window centered at its shown time; its width in the image is a display cell, not an exact event duration. The 128 logarithmic frequency rows summarize the strongest bin in each band, or the nearest bin when the band is narrower than the FFT spacing. Nearby low-frequency rows can therefore repeat the same bin.

Color is clipped to −100 through 0 dBFS. Display resolution, windowing and decoding affect the picture: a bright band is not necessarily a separate instrument or a diagnosis of hum. The view is not a calibrated sound-pressure measurement, a loudness meter or a spectrogram editor. For one detailed frequency snapshot use the audio spectrum analyzer; for more interpretation see how to read a spectrogram.

If you hear steady hum, compare several sections and follow the hum-removal guide. A filter can affect wanted sound at the same frequencies. Keep the original and compare any repair by listening.

A few useful answers

Free audio spectrogram questions

How do I create a spectrogram online?

Choose a supported MP3 or WAV, enter the start time and duration of a section up to 10 seconds, choose a channel if stereo, and select Analyze. Processing happens in the browser.

What do the colors mean?

Colors represent estimated frequency-bin levels in dBFS, from black at or below −100 dBFS to yellow at or above 0 dBFS. Frequency is logarithmic from 20 Hz at the bottom to 20 kHz at the top; time runs left to right.

Can I save the spectrogram as an image?

Yes. After analysis, choose Prepare labeled PNG, then Download labeled PNG to save a static image with the frequency and time axes, channel and color scale. The image does not contain audio.

How is this different from a spectrum analyzer?

A spectrum is one snapshot of level across frequency. The spectrogram displays a series of overlapping snapshots so you can compare frequency content over time.

Can it remove noise or identify a sound?

No. It visualizes estimated levels, not source identity or an edited recording. Listen and compare with other evidence before deciding how to repair a file.

Is my file uploaded?

No. The browser decodes and analyzes the selected file locally. No account is required.

After preparing your audio

Focus on the sound inside it.