Hey I know most of us have stock or modern after market horns, but I recently purchased an old style springer horn on the cheap because it wasn't working.  I came across this guide to diaphragm style horns and it really explained it well and helped me fix the horn which I am stoked about.  Just wanted to share incase anyone needs now or in the future a clear and concise explanation of how diaphragm style horns work and how to fix them  

http://www.ruiter.ca/mc/info/hornrep.html