These are topics relating to sound.
Such things as:
MicingALectern - What does/doesn't work for micing a lectern
{{Arisia09}} - Unorganized musings from Arisia09 sound.
http://www.bobmills.org/amu/ All Mixed Up - Originally a pamphlet, now a website, which is a great resource to learn sound engineering for folk music and dance events.