◈ Spectrogram Tools

See Sound.
Hear Images.

Three tools in one: generate a visual spectrogram from any audio file, convert an image into sound, or decode a spectrogram image back to audio. All in your browser — no upload, no signup.

Audio → Spectrogram PNG

Drop any audio file to instantly visualise its frequency content over time. Download the result as a high-resolution PNG image — perfect for sharing, analysis, or embedding in your ARG.

⊙
Drop your audio file here
or click to browse  ·  WAV, MP3, OGG, FLAC, AAC, M4A
Resolution
Frequency range
Color scheme
Gain (dB boost)   +0 dB
⊙ Drop an audio file to generate spectrogram

What is a spectrogram?

A spectrogram plots time (x-axis) against frequency (y-axis), with brightness representing amplitude. It reveals the frequency content of sound invisible to the ear.

AudioCipher patterns

AudioCipher's HZAlphabet produces a characteristic stepped-frequency pattern — each letter is a distinct horizontal band. The shape spells the message on the spectrogram.

Hidden images in audio

Artists like Aphex Twin have hidden images inside music tracks. Use the Image → Sound tab to encode your own picture into audio, then view it here.

Image → Sound

Convert any image into audio. Pixel brightness maps to frequency amplitude — brighter pixels produce louder tones at that frequency. The resulting audio reveals the image when viewed in a spectrogram. Inspired by artists like Aphex Twin who hid images inside music.

▓
Drop your image here
or click to browse  ·  PNG, JPG, GIF, WEBP  ·  any size
Frequency range
Duration   6 s
Sample rate
Invert (bright = quiet)
Volume   0.80
▓ Drop an image to preview how it will sound

How it works

The image is scaled to a fixed height (frequency bins). Each column of pixels becomes one moment in time. Pixel brightness sets the amplitude of each frequency at that moment.

Best image types

High-contrast images with clear shapes produce the most recognisable spectrograms. Simple logos, text, and line drawings work best. Busy photos become noisy audio.

ARG & music trick

Hide an image in your music, podcast, or Discord audio. Listeners who run the audio through a spectrogram analyser will see your hidden picture — a classic ARG technique.

Spectrogram → Audio

Upload a spectrogram image and recover the audio it represents. Use this to decode images created by the Image → Sound tool, or to attempt reconstruction of audio from any spectrogram screenshot.

◈
Drop a spectrogram image here
or click to browse  ·  PNG, JPG, WEBP  ·  any spectrogram screenshot
Min frequency (Hz)
Max frequency (Hz)
Duration   8 s
Tip: if decoding an Image→Sound file, use 200 Hz min, 16 kHz max, and match the original duration.
Sample rate

Best results

Works best on spectrograms created by this tool's Image → Sound panel. Screenshots of external spectrograms can be reconstructed — match the frequency range settings to the original.

Frequency mapping

The image rows map linearly from min-freq (bottom) to max-freq (top). Set these to match the spectrogram you're decoding for accurate reconstruction.

Limitations

Phase information is lost in a spectrogram image — reconstructed audio approximates the original. Heavily compressed or low-resolution images produce noisier results.