Audio Spectrogram & Waveform

Open an audio file or use your mic to see a spectrogram & waveform — playback, log/linear scale, perceptual colour maps, exact Hz/note/dB readouts, PNG & CSV export. Nothing uploaded.

See any audio file or your mic as a spectrogram and waveform — playback, log/linear scale, exact Hz/note/dB readouts, PNG & CSV export. Free, in-browser…

About Audio Spectrogram & Waveform

Audio Spectrogram & Waveform is a free, browser-based audio analyzer that turns an audio file — or your live microphone — into a colored spectrogram and a waveform you can inspect. Built on the Web Audio API, it decodes the file locally, computes the spectrogram with an FFT, and lets you play it back with a synced playhead while you hover for exact time, frequency, musical note, and dB readouts. Use it to spot pitches, harmonics, noise, or clipping, or to export a PNG image or a CSV of peak frequencies. Everything runs entirely in your browser — nothing is uploaded, and there is no signup.

How to use Audio Spectrogram & Waveform

  1. Pick a source with the toggle at the top: 'Microphone' for live audio or 'Audio file' to analyze a recording.
  2. For mic mode, click 'Start mic' and allow access; for file mode, drop an audio file (MP3, WAV, FLAC, OGG, M4A) onto the drop zone or click to browse.
  3. Switch between 'Spectrogram' and 'Waveform' views, choose a colour map (viridis, magma, inferno, grayscale, or classic), and set the frequency scale to Log or Linear.
  4. For files, tune the analysis with FFT size (1024–8192), Overlap (50/75/87.5%), and the noise-floor dB slider to reveal faint detail.
  5. Press Play and click anywhere on the spectrogram to seek, or use the seek slider; hover the spectrogram to read exact time, Hz, musical note, and dB.
  6. Click 'Download PNG' to save the current view, or 'Export peak frequencies (CSV)' to save a time/peak-Hz/peak-dB table.

Frequently asked questions

Are my audio files uploaded to a server?
No. Audio is decoded and analyzed entirely in your browser using the Web Audio API — nothing is recorded, uploaded, or sent anywhere, including live microphone input.
Is it free and do I need an account?
Yes, it's completely free with no signup, account, or watermark.
Which audio formats can I open?
It uses the browser's built-in decoder, so common formats like MP3, WAV, FLAC, OGG, and M4A work in most browsers. If a file won't decode, your browser may not support that format — try WAV, MP3, or M4A.
Is there a limit on file length?
Yes. Files are decoded fully into memory, so anything over 30 minutes is rejected — trim longer recordings first.
What do the FFT size, overlap, and noise-floor controls do?
A larger FFT size (up to 8192) gives finer pitch resolution but coarser timing; higher overlap (up to 87.5%) makes the image smoother over time; and lowering the noise-floor dB slider reveals faint detail. These analysis controls appear once an audio file is loaded.
Can I get exact frequency or note readings?
Yes. In file spectrogram mode, hover anywhere to see the exact time, frequency in Hz, the nearest musical note, and the level in dB; you can also export a CSV of peak frequency over time.

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