Audio Visualizer
An audio visualizer that splits whatever's playing into 1,024 frequency bands and draws each one as a bar, updated every frame.
The whole file
Drop a file and the whole of it is read into one picture: time across, pitch up.
The audio file
Drop an audio file
MP3, WAV, M4A, OGG and FLAC — the file never leaves this device.
The reading
View
Frequency axis
Log spacing from 20 Hz to the file's top frequency, so a position is a pitch rather than a bin index.
Bands
Bands group the live view. The whole file draws one column a slice instead.
−30 is the Web Audio default and a loud master sits on it. A full-scale tone reads −13.56 dB through the analyser's own window, so the scale has that much left in it.
Cut-off ruler
The reading
The reading names what the picture shows: how much of the file was read, where it stops, or the loudest band right now.
How to use
- Pick an audio file or drag one onto the box. Whatever your browser can play, the visualizer can draw.
- Read the whole-file picture, turn the cut-off ruler on if you suspect an upscaled MP3, then switch to Live bars and press Play to watch any passage. Pause or let the track end and the last frame stays where it was.
About this tool
Drop a track and the whole of it is read into one picture before you press anything: time runs left to right, pitch climbs from bottom to top, and brightness is loudness. A song's structure shows at a glance, and so does a file that stops dead at 16 kHz because it was encoded from something worse than its bitrate claims.
The picture comes from a 2,048-sample transform stepped every 512 samples across the file at its own sample rate, so a 44.1 kHz file has 21.53 Hz bins on every machine. Live bars, the second view, draw the same transform while it plays, grouped into 24, 48 or 96 bands.
The axis is octaves by default, so equal steps up the picture are equal steps in pitch, the way an ear hears them. Linear is there as a choice; on it everything under 1 kHz, which is most of what anyone would call the musical part of a mix, sits in the bottom few percent.
Bars are smoothed frame to frame so the picture does not strobe. Turn on reduced motion at the system level and the smoothing climbs further, which makes the whole thing noticeably calmer to watch.
I built it mostly to have something to point at. Describing what a bass drop does to a spectrum is hard. Showing someone takes four seconds. Run a pure tone from the Tone Generator through it once and the axis clicks into place: one spike, one position, sliding as you change the frequency.
Good to know
- No microphone input. It reads a file through the player and nothing else, so for a live check that your mic is picking up sound, the Voice Recorder's input meter is the right tool.
- Nothing is saved. The canvas is painted frame by frame with no recorder behind it, and there is no way to export the animation as a video or even a still. Screen capture is the workaround people use.
Things people ask
What are the bars actually measuring?
Loudness per frequency band, refreshed every frame. The analyser hands back 1,024 levels and the page groups them into the bands you chose, so the lowest bands hold a single bin and the highest hold over a hundred. The figure under the picture names the loudest band at that moment.
Why do loud parts flatten out along the top?
The scale runs from −100 at the floor to the Contrast setting at the top, −30 by default, in relative decibels. Push a band past the top and its bar sticks to the edge; when a quarter of them sit there for a second the page says so and points at Contrast, which lifts the ceiling.
Can I visualize my microphone instead of a file?
Not on this page. The graph is wired straight off the audio element, so there is no path in for a live input. The Voice Recorder shows a real-time level meter while it captures, which covers the usual reason people ask.
Can I record the visualization for a video?
There is no export here. What you see is painted to a canvas and discarded just as fast. People building stream overlays generally capture the window with OBS or their operating system's own screen recorder.
Why does my old MP3 look empty above a certain point?
Because it probably is empty up there. Lossy encoders discard the top of the spectrum first, and a 128 kbps MP3 is often cut off somewhere around 16 kHz. That flat stretch on the right is a genuine hole in the file.
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