You can also make your own shaped ply thing like that by cold moulding over an existing shape. A 3D print will be a handy former to make repeatable cold moulds over
The youTube algorithm is figuring out I want to see spheres. This DIY MBL style driver came up in a seven year old video today by James Meacham . I will have to watch the other videos to see if there are any construction details.
There was some information on the extensive build process of that project I remember. Sorry, I don’t have any links…
This driver is impressive. Looks large and had to be built to be very light yet rigid. Its "pistonic" movement of air must be the top and bottom hemisphere portions moving in each direction given the location of the motor. Maybe in effect a way to build a large domed driver with 2-way propagation? Better to orient it horizontally?