RockBox + Refurbished MP3 Players = Crowdsourced Audio Capture

An anonymous reader writes "Looking for an inexpensive means to capture audio from a dynamically moving crowd, I sampled many MP3 players' recording capabilities. Ultimately the best bang-for-the-buck was refurbished SanDisk Sansa Clip+ devices ($26/ea) loaded with (open source) RockBox firmware. The most massively multi-track event was a thorium conference in Chicago where many attendees wore a Clip+. Volunteers worked the room with cameras, and audio capture was decoupled from video capture. It looked like this. Despite having (higher quality) ZOOM H1n and wireless mics, I've continued to use the RockBox-ified Clip+ devices ... even if the H1n is running, the Clip+ serves as backup. There's no worry about interference or staying within wireless mic range. The devices have 4GB capacity, and RockBox allows WAV capture. They'll run at least 5 hours before the battery is depleted (with lots of storage left over). I would suggest sticking with 44kHz (mono) capture, as 48kHz is unreliable. To get an idea of their sound quality, here is a 10-person dinner conversation (about thorium molten salt nuclear reactors) in a very busy restaurant. I don't know how else I could have isolated everyone's dialog for so little money. (And I would NOT recommend Clip+ with factory firmware... they only support 22kHz and levels are too high for clipping on people's collars.)" This video incorporating much of that captured audio is worth watching for its content as well as the interesting repurposing.

Lots of work?

[mpoulton]

Maybe I'm misunderstanding the process here, but this seems like it would create a HUGE amount of editing work. Are you manually switching which recorder's audio is used as different people speak? In other words, editing the video using as many simultaneous audio tracks as there are recorders, syncing them, and using the best one at any given instant during the video? That seems like it would add huge amounts of editing time.

Another use for the Rockbox recorder

[StealthSock]

My ears got plugged up while swimming and I could barely hear the next day. Rockbox's recorder function outputs the microphone to headphones even when it is not recording. That $30 Clip+ worked reasonably well as a makeshift hearing aid, as long as I was facing the person I was trying to hear.