Separate air from objects inside the box
Net volume is the air volume used by the response model. Gross volume is the rectangular internal space, including the space later occupied by driver, braces, port and other objects. Here gross equals net plus the displacement allowance supplied by you.
The tool fixes external width and height, subtracts twice the wall thickness, and solves the required internal depth from gross volume. It adds front and back thickness to obtain external depth. This avoids silently treating an outer dimension as an inner one.
Read the joint convention
The front and back cover the entire external width and height. Side panels sit between front and back but extend over the full external height. Top and bottom sit between all four of those panels. Six rectangles follow directly from this convention.
The cut list reports finished panel dimensions. It does not arrange panels on a sheet or add blade kerf, trim stock, joint clearance, rebates or bevels. The material area is the sum of six rectangles, not a purchase recommendation or a packing solution.
Check construction details outside the rectangle model
No cutout is drawn because a driver name or nominal diameter does not specify its mounting details. Actual basket depth, magnet clearance, fasteners, terminal cup, bracing and port placement must be checked separately. The calculated depth can be mathematically valid while the intended assembly does not fit.
Use the PDF as a dimensioned record and the millimeter SVG as a vector reference. Printing the PDF at full page size does not make it a full-scale cutting template. Measure a known SVG dimension after importing it into another program before relying on its scale.