The Australian Navy needed to recruit Electronic Spectrum System Operators. It’s an intelligence role that’s difficult to recruit for and involves identifying threats by manipulating frequencies in the electromagnetic spectrum – also known as The Invisible Battlefield. So, that’s where we ran our ad. With a small budget for social media, we created a single audio file that was so much more than something to listen to. We challenged people to analyse it, decode it, manipulate its frequency content and discover its hidden message – a recruitment poster, painted with sound.

The Audio Ad You Can See is 56 seconds of audio. But hidden inside the audio is an an image – our recruitment ad. To 99% of Australians, all they would hear is sound. But the 1% we needed to talk to would see our ad. The audio needed to be processed with a spectrogram. It’s a tool that analyses frequencies in the electromagnetic spectrum and is used by tech experts to analyse sound. It’s also used by the Navy to analyse frequencies and identify threats that can’t be seen. Only those with the right problem-solving abilities could find the hidden message and get the direct link to the job listing. The result was an audio ad that was also a print ad, a social post, user-generated content, a direct recruitment campaign, and an innovative way for the Australian Navy to find its new intelligence recruits.

This audience is notoriously hard to reach. They’re interested in technology and problem-solving, so connecting with them required an idea that challenged them and invited participation. The Audio Ad You Can See did that – it asked them to roleplay as an intelligence officer and use the same technology they would in the Navy. Not everyone could find the hidden message, so we knew the people visiting the job page were high quality candidates – they had found the direct link to the website. The collection of data was a simple process in tracking downloads, streams, social interactions and visits to the job page.

Creating an audio ad with a print ad hidden inside it was a unique design collaboration between an audio engineer and a visual designer. While the audio needed to be crafted for an image, the image needed to be crafted for audio. First, a designer created a poster. It was then converted into audio signals using an image synthesizer, before the voice and further soundscape elements were added. Extensive use of additive EQ, subtractive EQ, compression and the micro-automation of volume were meticulously used to ensure each sound its own sonic space in the frequency spectrum. The audio also contained other hidden sounds to misdirect the audience, like sonar pings, whale sounds, muffled communications and Morse code – with its own hidden message that spelled out ‘KEEP LOOKING’. The audio was released on social media.

This was one of the Navy’s most successful direct recruitment campaigns. On social media, it had more interactions than any other organic post from Australia’s Defence Forces with 512% more impressions, resulting in 80 times more engagement with the job listing, all from high quality candidates. The Audio Ad You Can See gave high quality candidates an experience that went beyond listening to an ad or looking at a poster – it put them in the shoes on an Electronic Spectrum Systems Operator and helped them imagine an intelligence career in the Navy.