How to Create Images Hidden in Audio
Spectrogram art is an image encoded into an audio file. The image is invisible when you listen — it only appears when the audio is viewed in a spectrogram analyzer. This guide walks you through creating your own, from choosing an image to viewing the final result.
Step 1: Choose Your Image
The best images for spectrogram art are:
-
High contrast — bold blacks and whites produce the clearest results
-
Simple shapes — logos, text, silhouettes, line art
-
Clean backgrounds — solid black or white, no busy patterns
Photos and detailed artwork work too, but the results are most striking with bold, graphic images. Think album covers, not vacation photos.
File requirements: JPG, PNG, or WebP, up to 10 MB.
Step 2: Choose Image or Text
Img2Sound offers two modes:
Image to Spectrogram — Upload any image file. Your photo, logo, or artwork gets encoded into audio.
Text to Spectrogram — Type any message. Choose from 16 fonts. Your text appears in the spectrogram.
Step 3: Set Your Parameters
Frequency Range: Where in the audio spectrum your image appears.
-
Low (20–350 Hz) = deep bass rumble
-
Mid (350–6000 Hz) = most visible in default spectrogram views
-
High (6000–20000 Hz) = high-pitched, less audible
-
Custom = set your own exact range in Hz
Duration: How long the audio file plays.
-
5–10 seconds for simple images
-
15–30 seconds for detailed artwork
Step 4: Download Your WAV File
Processing takes under 60 seconds. You get a lossless WAV file ready for:
-
Viewing in a spectrogram viewer
-
Layering into music productions
-
Sharing as a standalone audio file
-
Embedding in podcasts or videos
Step 5: View the Result
Open your WAV file in a spectrogram viewer to see the hidden image:
Audacity (Free): 1. File → Open your WAV 2. Click the track name dropdown → Spectrogram 3. Adjust frequency range in Spectrogram Settings to match your chosen range
Spek (Free): 1. Drag and drop your WAV file 2. Image appears automatically
Tips for the Best Results
- Start with text — typed messages are the easiest to verify and share
- Use the mid-frequency range (350–6000 Hz) for your first attempt — it's the most visible in default viewer settings
- Share both the audio file AND a screenshot of the spectrogram when posting online — most people don't have a spectrogram viewer
- Layer into music by importing the WAV into your DAW and mixing it with existing tracks at low volume
- Try the inaudible range (16–20 kHz) for truly hidden content that most adults can't hear
Start Creating
Sign up free and get 3 credits to try it — no credit card required. Each credit produces one custom WAV file at your chosen settings. Or grab a $1.99 bundle for 10 WAV files across all frequency bands.