http://www.stormcam.org/cable-earpiece/
How to beam 13 microphones on line 1?
My classmates can not hear with a microphone (for teachers) and a piece of ear, he has to wear. I want everyone to wear a helmet and connect all the cables microphone * something *, so it can connect a single cable in his earpiece. In this way, he can hear all of us, instead of the teacher. It is missing a lot of conversations. Someone Has he any idea?
you'll need a mixer 13 in place, as a 16 channel mixer.
Apple In-Ear headphones first look