What goes into developing a great duck call?

To get consistency during the development process, we moved away from all hand-tooling and leveraged technology, like 3D CAD models and CNC machining.  Gave us repeatability of the design, and consistency in the application of changes.

Get away from doing things by eyeball, get into a real design process.  Ability to experiment with design changes.  Have certainty in the difference between designs, that it is actually the design change and not human error.

Barrel length, insert length, back pressure chamber, curvature of tone board, all affect the sound quality, air speed requirement, etc.