Passive amplification is amazing for what it can do to the audio from a tinny little speaker. The iPhone7 adds a stereo speaker at the top of the phone face alongside the previous speaker on the bottom of the phone. This passive amplifier has pickups in both locations to reproduce the stereo sound and double the amplification.
Also, many amplifiers are quite tinny in their amplification because they expand the cone very quickly. This amplifier is all about length, the pathway for each high band amplifier is 200mm long and expands 8x over this length.
The mid and low-band frequencies are treated to a 400mm path expanding 5x over that path. The lower expansion over a longer distance helps the low band amplify better.
While not the same quality as a good Bluetooth speaker, it sure is a lot more fun to build!
There's a lot of overhangs, but all the big ones have been accommodated so don't print with any supports.
There is a support built into the model for the impossible overhang of the face mounted speaker. This is trimmed away before use.
This was done completely in OpenSCAD. However, if you want to open this file, be warned it takes a long time compile. The final render of this model took 1h30m on my system. To speed up any design changes, open the file and scroll towards the bottom, there are 5 lines that are indicated "remove for F5 support", comment these lines out and the model will render without the interior cones and without the automatically generated support structures. Add these line back in and press F6 to wait for an hours long render.
There are two small rectangles on either side of the model, these are there to make sure that the 6" print width of many printers will be able to print this model once the first layer is done and not wait until many hours into the print. Throw them away after build.
The spline distance is borrowed from the
bezier.scad file which is included as a download. It is also available as http://www.thingiverse.com/thing:8443.