I want a quick-and-dirty prototype, so I am thinking about using a .23 cu. ft. Denovo CNC MDF box kit from Parts Express (6.9 Liters). There will be a 5-inch woofer on the front panel, and a 5-inch passive radiator on either side, for a total of two. Woofer and Passive Outside Diameters are 5.8 inches. Cabinet EXTERNAL DIMS 11.5 H x 7.5 W x 8.5 in. D. The front-panel woofer position will be dictated by the tweeter's OD of 110mm (4.33 in.). However, the side-mounted passive radiators can be moved around a bit within the side panels; which, seen head-on from the side view, are 11.5 in. High and 8.5 in. Wide. In terms of up and down and left to right, are there any valid engineering reasons for choosing a position other than at the center of the X made by the two diagonal lines? I am somewhat tempted to displace the center of the opening for the passive radiator from the 50/50 position, to a position of 61% up from the bottom, and 61% toward the rear of the box. Why? Because I am, at heart, a 14th-Century Irish Peasant, and Phi, the Golden Ratio Constant, is my favorite Superstition and Totem. All comments welcome; and, have a great weekend.