How it works

  1. Drop your audio file. MP3, WAV, FLAC, AIFF, OGG or M4A up to 500 MB — it's decoded locally, nothing is uploaded.
  2. Read the spectrogram. Frequencies on a log, linear or mel scale up to half the file's own sample rate (beyond 20 kHz on a 96 kHz file), time left to right, level in dBFS as color. Hover or tap to read frequency, note and cents, level and time, and play the track to follow the playhead.
  3. Check the report and export. An automatic analysis sums up band balance, resonance candidates, high-frequency extension and approximate dynamic range — then export the image as PNG.

Features

  • 100% in your browser. Your track never leaves your computer — decoding, FFT and rendering all run locally with the Web Audio API.
  • Log, linear or mel display at the file's native sample rate. The log scale matches how we hear, so bass detail isn't crushed at the bottom of the image; the linear scale is the reference view to spot a lossy-encoding cutoff or an upsampled MP3. FFT size (up to 32768 on a computer), display range (60, 80 or 120 dB) and channel (Mid, Left, Right, Side) are adjustable.
  • Automatic mix report. Energy balance across frequency bands, detected resonance candidates, high-frequency roll-off (a clue to lossy encoding) and an approximate dynamic range measure.
  • Synced playback and PNG export. Listen with a playhead moving over the image, then save the spectrogram as a PNG.

FAQ

Is this spectrogram tool free?

Yes. Without an account you get 2 free analyses per day across AudioKit's free tools; with a free account, 5 per day. If you need more, AudioKit Premium removes the daily limit. There's no watermark and no feature lock: the free analysis is the full analysis, including the report and the PNG export.

Is my audio file uploaded to a server?

No. The spectrogram is computed entirely in your browser using the Web Audio API: your file is decoded and analyzed on your own machine and never leaves it. The only network call is a tiny anonymous counter that tracks your daily free quota.

Which audio formats are supported?

MP3, WAV, FLAC, AIFF, OGG and M4A files up to 500 MB. That covers everything from a quick phone recording to a full-length lossless master. If your file is in another format, run it through our free audio converter first.

How can a spectrogram help me diagnose my mix?

It shows problems your ears suspect but can't pinpoint: a resonance appears as a thin horizontal line, harsh sibilance as bright bursts between 5 and 10 kHz, hum or broadband noise as a constant carpet, and low-end masking as a dense, smeared bottom. AudioKit also generates a report with band balance, resonance candidates, high-frequency extension and approximate dynamic range.

How do I read a spectrogram?

The horizontal axis is time, the vertical axis is frequency (low at the bottom, high at the top — log scale here, like our hearing), and brightness is intensity: the brighter, the louder. Typical patterns: stacked horizontal lines are the harmonics of a note, a vertical stripe is a transient like a drum hit, a uniform haze is noise, and a hard ceiling around 16 kHz is the signature of lossy encoding.