Watch the YouTube Tutorial for full build.
Using Inventables easel.com CNC software you can quickly combine circles of various sizes and depths to make the cone to amplify the sound using the align tools.
More images and information can be found here http://www.onewood.com.au/x-carve-cnc-project-make-a-passive-amplifier-for-your-iphone/
Clamp the project to the X-Carve cnc machine, you can use the below link for the free plans in easel for the hold down clamps i use. You can use these on your X-Carve to cut them out.
The project is made from 2 pieces of framing timber about 150mm long laminated together and smoothed with a hand plance.