well on one of the ones in the sca documentary you can here someone shouting orders above that music. I believe it is in the open field battle or one of the other ones below.
I found these awesome videos on these sites. I've been wanting to do this for a long time but haven't found a place near where I live. http://scadocumentary.com/trailer.asp http://www.jubilex.com/ This has to be the closest thing to real medieval combat out there.