Turns out you can embed secret images into your music… Here’s how!
**IMPORTANT** an UPDATED VERSION: GO NOW
A long time ago I taught you all how to embed text into your music, now I am going to teach you how to embed an image in there as well!
I didn’t know about this until yesterday when I read this post about a code in one of my favorite shows Archer. In the second episode of season 6 there is a computer screen which displays information about a character and in that data there is a hexadecimal code. Translating that code into letters starts you on a long and wild chase down a rabbit hole on the internet.
One of the stops along the way leads to an audio file of strange noise. That noise has a message buried in it and can be exposed using a spectrograph. That is what this post aims to demonstrate. Both the construction and visualization of these things!
Turns out people have been doing this to music for a long time. Aphex Twin, Nine Inch Nails and Pendulum to name a few.
At the end of “Axle Grinder” by Pendulum, for example, there is what sounds like a standard white noise impact. However, if you run that sound through what is called a spectrograph you get this image.
First, how to do encode ( embed ) photos into audio.
We will use a free program called Coagula.
DOWNLOAD –> Coagula.
Coagula; What is it?
Coagula is an image synth. This means that it is both a simple image editor, and a program for making sound from those images.
Coagula; How does it work?
Coagula uses one sinewave (beep) per image line, one short blip per point (pixel) on the line. Red is left, Green is right, Yellow is green+red, so it’s in the middle. Blue makes each sine into a narrow noise-band, so you can create hard noise or organ-like sounds.
Help / Instructions
The program uses bitmap images ( .bmp ). Find or Make a small .bpm image file. Alternatively, inside the program you can draw or write something. Then go to the “sound” menu. There choose “Render Without Blue” or hit F6 on your keyboard. Once that has completed. Go to “File” and “Save Sound As…”. That raspy white noise .wav file contains the image. You can make sure by using RX or Coagula.
It might be a good idea to go to the render settings and set the pitch range a bit higher than the default. I think 1000 low and 8000 high is a good spot. You also want your image to be long rather than tall so that it fits into the window.
A PDF Manual can be found here.
Second, How to decode ( view ) the hidden messages in the audio.
Here we simply bring the audio file into RX and swing the viewer over to show only the spectrograph. There you will see the message or picture you coded in step one.
Video Tutorial on this Process!
This video tutorial walks you through how to view hidden messages embedded in audio as well as how to make them yourself!
I also get into Ableton Live to add more sounds to the raspy hidden message audio to mask it out. I talk a bit about what kind of EQing needs to be done to retain the message behind the rest of the new audio.