Glass spherical speaker which needs no processing of glass.
I used cheap glass bowl sold in DAISO (200 yen) and FOSTEX FE103En full-range speaker unit.
The dimension of glass bowl has slight individual difference, so this thing is marked as work in progress and mainly for sharing idea.
You need 3.5 x 8mm tapping screws to fix the baffle to the glass bowl. Rubber bands are necessary to seal between them. Electric wires and connectors are also necessary.
Assembly
Insert thick rubber band as a seal between baffle and glass bowl.
Screws are used to fix the glass bowl to the baffle plate, then attach the speaker unit.
Spherical shape of the enclosure inherently suppress unintended echo, however, if you feel some sharp resonance sound in high frequency it is useful to place fluffy objects in the enclosure.