I've accumulated a few pairs of broken headphones that I wanted to turn into small desktop speakers.
I've started with the most recently lost pairs, a cherished set of Sony Studios that produce enough sound to act as primary speakers for my computer.
Plastic: Hatchbox PLA 1.75mm
Headphones: Sony MDR-7502 Closed-back
Printer: Monoprice Mini
I initially wanted to make a set of tiny speakers from the more standard size of headphones.
I'm working on another project to make hoods for my mamiya lenses and some principles from that apply to building the tiny speakers. So, first the lens hoods, then the little speakers :)