Hey, i'm gonna spill out all kinds of info so make sure you understand it, hehe. I'm currently workin on your design right now, you will be using external dimensions of 42" wide x 17" tall x 22" deep. This IS what i am going with. You will be using a double baffle on this box. Box material will be constructed out of 0.75" material. I need to know what bracing material you will be using, Wooden dowels or 2x4s? Internal dimensions- 40.5" wide x 15.5" tall x 19.75" deep. Your speaker Outer Diameter is 10.91", i went ahead and rounded up to 11" for a hair more headroom for accidental measurement inaccuracy. Your Baffle design- The border around this baffle is showing the thickness of the wood. I wanted to show you that ALL the subs will have 1 point that will be screwing into an adjacent piece to hold the subs to the baffle. This is not a problem, i just wanted to let you know this. I made sure that no subs would need to be screwed through the floor. Here are the CENTER points for which the subs will be mounted. Do NOT shift these points or your subs will not fit. To make sure they will fit before cutting out the holes, take a compass and put it on the center point and draw an 11" diameter circle(5.5" radius) and NO circle should overlap another. They will come close but will not overlap. These measurements are being measured from LEFT to RIGHT, Bottom to TOP- Sub #1- 5 17\32" x 6 9\32" Sub #2- 15 11\32" x 11 7\16" Sub #3- 26 3\4" x 11 7\16" Sub #4 - 36 15\32" x 6 9\32" Those are your center point locations for drilling\cutting your mounting hole. I will now be working on your port and Bracing design. PLEASE tell me what material you will be using for bracing so i can get this done tonight.