Hi all, I could really use some help on this. I don't know much about sound, but right now I'm the guy who is figuring out how to do sound at my high school. I'm trying to understand the whole system and there is a part that I don't get. So the HL and the HR speakers run into something called tie lines from AVP's. We also have a HC speaker but thats not patch in the patch bay at the moment b/c I don't understand the how the HL and HR speakers are patched. Those speakers work but I have no idea how its run into the sound board which is an LS9-32 or where it is run to. I also don't have any control over the speakers they just work. (What I mean is I can't change the control of the speakers to a different fader) Right now the speakers work when I turn up channels 31 and 32 which is the input channels from our Mac Pro. If anyone has any idea what I'm doing wrong or what I need to do that would be great. Also if someone could tell me what does tie lines from AVP's mean? Thanks in advance!