I want to run 4 mains(tops) and 2 subs for an outdoor digital music gig. No live performers. Wondering. Is there a preferred way to set this up? Typically I set the 2 mains about 4 feet apart from each other 20 to 25 feet apart and place the 2 subs next to each other right in the center. I learned a few things here already so figured I should ask and get ideas. No stage...all set up at ground level. The mains are 15 inch 2 ways and the subs are passive 18's.