Embed A Code In Pop Song

In Colombia:

The team began experimenting with Morse code using various percussion instruments and a keyboard. They learned that operators skilled in Morse code can often read the signals at a rate of 40 words per minute ­ but played that fast, the beat would sound like a European Dance track. "We discovered the magic number was 20," says Portela. "You can fit approximately 20 Morse code words into a piece of music the length of a chorus, and it sounds okay."

Portela says they played with the Morse code using Reason software, which gives each audio channel or instrument its own dedicated track. With a separate visual lane for certain elements, it was possible to match the code to the beat of the song -- and, crucially, blend it in.
Hiding the Morse code took weeks, with constant back-and-forth with Col. Espejo and the military to make sure their men could understand the message. "It was difficult because Morse code is not a musical beat. Sometimes it was too obvious," says Portela. "Other times the code was not understood. And we had to hide it three times in the song to make sure the message was received."