Ben Cartwright-Cox observed that he could modulate the bass frequencies in electronic dance music/dubstep in a way that was easy to detect with a signal processor and inaudible to his unaided ears, so he wrote some code to hide messages in the wubwubwub.
He's written up the technique in plain-language math that doesn't require a background in signal processing to understand.
The obvious downside, I think, is that this really isn't hard to find with signal processing software, so it is of limited use as a technique for hiding the existence of a bitstream — any adversary that wanted to look for this kind of modulation would easily find it. Of course, you can (and should) also encrypt the message, but you're still losing the steganographic signal-hiding.
But it is an interesting data-channel! Maybe DJs could encode messages into their mixes that could be interpreted and acted upon by the dancers' wearables? Admittedly, this would be way less efficient than, say, Bluetooth, but it would be pretty cool!
Encoding data in dubstep drops [Ben Cartwright-Cox/Benjojo]
(via Four Short Links)
(Image: Bobmilkman, CC-BY-SA)