Because he wanted too provide a simple solution to eliminating everyone’s habit of cupping their phones to increase the volume. And because he did not wanted to have to buy/carry a bluetooth speaker, 3DSolio has created this very cool 3D printed passive amplifier.
His MiniAmp is easily 3D printable, he tried it with success on a Wanhao Duplicator, a M3D Micro
and a PrintrBot Metal Simple.
You can download this really useful 3D model on Cults here: https://cults3d.com/en/gadget/miniamp-v1-0