It's the guts out of an old Radio Shack 32-2015 Voice Amplification system. You don't use the casing or the speaker or the battery pack, just the electronics parts. The original system ran off 6 AA batteries, at 1.5 volts each equals 9 volts, so we swapped out the big AA pack for a single 9v connector. Then put the electronic board guts inside a little plastic box to protect them. The plastic box gets velcroed to the inside of the the helmet. I chose the back left side to mount it in. Doesn't hit my head or ear having it there.
Then, take tin snips and cut the headset part that goes around your ears off. You're then left with the little flexible boom mic and the connector. I velcroed this to the right cheek of the helmet, and the boom hangs by your mouth in front of the visor.
The small laptop speakers don't pump out huge amounts of volume, but really I'm just using this system to talk to people who are talking to me, without them having to lean into me to hear me reply to them. You wire the 2 speakers into the original wires for the one speaker that came with the voice amp. Run them in a big loop like this......
Red wire from the voice amp into the red wire of the first speaker. Black wire of the first speaker into the red wire of the second speaker. Then black wire of the second speaker into the black wire of the voice amp, completing the loop.
Instead of gluing the speakers into the helmet, I just taped them in place with that metallic chrome tape used to tape heating pads on the the aquarium walls of reptile or amphibian tanks. I then covered the chrome tape up with some olive drab duct tape I had around, so it wouldn't be so shiny inside my helmet.
The other guy who gave me the layout of this helmet glued his speakers and boom mic right into the helmet. I have pics of his layout I'll email you if you send me your email. He also didn't put the plastic box over his electronics board, but I wanted to protect it some.
