Comment tl:dr Recipe for recording the audio of multiple i (Score 5, Informative) 66
tl:dr Recipe for recording the audio of multiple individuals in a large crowd.
Ingredients:
Sandisk Sansa Clip+ MP3 Player - http://www.sandisk.co.uk/products/sansa-music-and-video-players/sandisk-sansa-clipplus-mp3-player
Rockbox - http://www.rockbox.org/
Instructions:
Install Rockbox (open source firmware for MP3 players) on the Sansa Clip+. Configure to record on the Sansa Clip+ microphone in
Gather all Sansa Clip+s at the end of the session, and extract the
Mix and fade between the tracks to isolate the audio of single conversations between participants.
He basically has created a relatively inexpensive and reliable way to get this audio. Much like using multiple Go Pro cameras to record action of sports events beats out using professional equipment (and in some ways has become professional equipment). He's arguing that the Sansa Clip+ together with the Rockbox open source firmware, is a better solution than using professional radio mic's and then having recording equipment receive those signals and store them on disk for editing later.
I've no idea how "crowdsourced" fits into this though, nor how this is anything more than an advert even though the solution is a little interesting. It's useful enough and potentially cheap that you might imagine giving everyone at a Ted one of these as the conversations caught off-record might be even more valuable than the sessions.