In light of 3D printing capabilities, I wonder how a DIYer would "invent" a moving coil driver today? Would there be a structure in front of the cone? To hold the cone other than today's surrounds? A second spider? Long and narrow with three magnets?
Something not round? Mounted differently than the hole-and-screws on a front board?
Something not round? Mounted differently than the hole-and-screws on a front board?