This Passive Speaker is dedicated to smartphones with speakers and power socket at the bottom.
The design has been shamefully derived from David Riesenberg's design for the OnePlus One.
Unlike his, this design is parametric, so you can adjust it for your Smart Phone.

It consists of four parts:

* The PipeStand is the main part, all others are put inside and glued

* The Insert is at the center, it guides the phone plug and supports the phone

* The LeftHorn

* The RightHorn

Customization

Open the SCAD file with OpenSCAD and change the different values in the "Settings" section to fit your phone and phone plug dimensions. Then generate, one at a time, the "PipeStand" and the "Insert" modules and export them to STL. The parametric design doesn't modify the horns, but they are not completely identical to David's ones. Their base has been planed a bit to have a flat face, more convenient to glue them. The provided STLs of the horns can be printed immediately. The STL files of the PipeStand and the Insert are just provided as an example. The DXF file is used by the SCAD file so they have to be in the same directory.