Horn Adjustment

[rmmccon]

My '46 Chief Horn barely makes any noise. It looks new and/or is a reproduction horn. I opened it up and noticed there are two screw adjustments, one in the front and one in the rear. Any tips or suggestions? It appear the front adjustment is for controlling the diaphram off of the coil. What does the rear adjustment do? Can I use a bench top 6 volt power supply while attempting to tweak the horn?

[pisten-bully]

I found this article very helpful: http://www.ruiter.ca/mc/info/hornrep.html