Step 5: Mark the locations of the speaker holes
To make sure they are exactly 120 degrees apart, used a piece of heat shrink tubing (or the like) to measure the circumference of bowl. Then divide the circumference by three, and used the same tubing to mark where the center of each speaker should be.
NB: For one hemisphere I centered a speaker on the handle and measured from there. The other hemisphere has a speaker centered on the spout. That way, the speakers are offset when you put the hemispheres together. Also, make measurements from both directions to make sure there aren't any errors.
I decided to put the speakers an inch away from the rim of the bowl. That left me clearance to put the lids back on, if I wanted to. Don't put them any further away, or they will wack into the top speaker.
Use your template to trace the speaker hole onto the bowl.