Hey Guys,

I know there hasn't been a lot happening in this group, but hopefully someone will chime in to answer my question...

I have this old phone receiver and want to make a couple of harmonica mics.  In the research I have done it says either side (speaker or mic) will work.  The ear-side, speaker part is very straightforward.  The mouthpiece side however is not so much...

Can someone explain to me how these connections even work?  Will the speaker side require additional power from something like a 9 volt in order to work?  If so, is the battery what I would connect to the red and black wires on the marbled plastic piece in order for that element to work?