What do these switches do and how do I go about setting them up?

Thanks in advance

Not sure about the Audio/Video switch, I don't believe my EP350 as one? In regards to the phase switch, this switch adjusts so your subs driver is in phase/out of phase with your l/r mains. Most people don't hear a difference, but it is my understanding you want them moving in/out at the same time. I found some music with a lot of low end frequencies, and played it with the switch in one position, then backed up to the beginning and switched to the other setting. You will notice the difference. I have my volume set at 12 o'clock and my receiver crossover at 80hz, and my sub crossover turned clockwise all the way to get it out of the way.

good luck

If the subwoofer is about the same distance from your seats as the main speakers leave the switch on 0 and don't worry about it (or try the following tests anyways).

If the sub is way off to one side play something with deep bass (preferably a mix of frequencies) and have SOMEONE ELSE flip the switch between 0 and 180 while you are sitting in the normal listening position. You won't hear much difference if you flip the switch while standing by the sub.

In general, stay with the position which gives you the most bass.

My EP350 is right next to my left m60 in our living room and I found that 180 phase produced the best results. I'm sure once I move everything downstairs to my "underconstruction" HT everthing will change.

Wayne, on the audio/video switch, subs which have that sort of thing insert a boost in certain bass frequencies when the "video" setting is selected, making the response less flat. Supposedly this might sound more impressive for certain effects in movies. My view is to use the "audio" setting for all material to get the flattest and most natural reproduction.