Encoded Message

This week I’ve been listening to the latest release by TCF (Lars Holdhus) on Liberation Technologies, entitled 415C47197F78E811FEEB7862288306EC4137FD4EC3DED8B.   Like his previous releases, each track title looks like an MD5 checksum – a string of letters and numbers that encodes the digital fingerprint of a file. A description of the release on Bleep.com suggests that “there are hidden keys in the track’s titles that unlock the full meaning of the work”. I haven’t been able to decode those titles, but I did notice something unusual in the visualizations of the last track – ’97 EF 9C 12 87 06 57 D8 B3 2F 0B 11 21 C7 B2 97 77 91 26 48 27 0E 5D 74′. Playing in foobar2000 and using its spectrogram visualizer, some unusual shapes are visible in the mid to upper frequencies that look almost as if they are cut-out. Here’s a foobar2000 spectrogram of the whole of track 7, which is just 29 seconds long (click to enlarge):

The five vertical red/yellow features are a slowed-down voice saying the word ‘slow’, but what caught my attention was the pattern in the background – the dark blue shapes with sharp edges. I wondered whether TCF had used some kind of spectral manipulation tool that allowed for the frequencies to be cut up in this way – like SPEAR or FreqTweak, for example. Then it occurred to me to that the shapes are squished at the top because this is a spectrogram plotted on a logarithmic frequency scale. So I made another spectrogram on a linear frequency scale, using the free software Sonic Visualizer, and after a bit of tweaking this was the result (click to enlarge):

It’s rare to see an image so clearly in a spectrogram. It’s clear enough to be able to search for visually similar images online, which reveals that it’s a photograph of violence during political protests in Greece, 2011: http://www.themysteryworld.com/2011/08/greece-protest-photos.html