I've been speaking with a flawless female voice for a couple of years now, but I still can't yell without sounding weird. It always makes me nervous about getting into arguments. 
For some reason I do fine yelling over loud music at clubs though. 

I just remembered when I was in the army and there was a day when I had to command a whole bunch of people at once. The others were laughing at me because I was unable to push out a loud voice and as I was trying real hard, I looked like I was angry I wasn't.

Later I realized that my shouting voice came from the mouth (or whatever you call this formation) and not from the throat as it should've been if I was a real man (pfff, I never knew what that is). And that's why it was so weak. I didn't do it on purpose though, it just came out that way

g