im trying to wrap my head around how to build a 4th order box, but it seems the more i read the more im second guessing things. my question where do i start on designing a box, what factors do i need to consider? i have 24 cubic feet to work with before woofer, bracing, and port displacement will i have enough room? its for 4 obsidian 15s. i want to tune around 45-50 hz. if someone can lead me in the right direction or help me figure out where to start that would be awesome!