Exponential Waveguide for 25mm Tweeters

Waveguide with 31.75mm throat and same 148mm cutout diameter of the Visaton waveguide. This one has 4 screws and a similar, but slightly different curve. The Visaton appears to blend two curves. I used a conic curve with rho of .38 to create the profile. It should offer similar performance with a smaller throat.