signal2wav / signal2sound in honor of Lucier/Dewan

[stephenwhitmarsh]

Reading on the history of EEG-music, and especially the first attempts by Dewan and Lucier.
The chapters on Dewan and Cybernetics, in Earth Sound Earth Signal, Energies and Earth Magnitude in the Arts (Kahn, Douglas, 2013) clearly explain the process and results of their first works - i.e. Music For Solo Performer (Lucier), especially around page 90-110. You can find a PDF here:

http://tle.li/texts/Kahn%2C%20Douglas%20-%20Earth%20Sound%20Earth%20Signal%2C%20Energies%20and%20Earth%20Magnitude%20in%20the%20Arts%20%282013%29.pdf

I thought it might be interesting for creative, historical and didactic purposes to include a module to do exactly the same: convert EEG to audio, or rather to subsonic sounds that move speakers, which then sympathetically resonate other objects. Rather than simply amplifying analogue, as they did, it will be a bit more involved for us (ADDA-conversion), but clearly we could do it. What we learned so far we need:

1. running filter. A high-pass is implemented in COGITO and preprocessing. We need to extend it to bandpass (e.g. for alpha).
2. writing buffer to soundcard (and wav), also already implemented
3. a DC-coupled, or at least very low-freq range audio-interface. I'll look up our previous correspondences on that. Not sure it won't work on cheaper, standard interfaces with enough amplification, as frequency response is hard to find.

These might relate to issues: #117 and #208
Perhaps we can find a way to discuss these in London.