Calculations for bell frequencies / notes?

[Bradygoldminer]

Hey Everyone,

I heard that there was a math formula to calculate the shape of a horn bell flare to play a specific note or frequency. I also do recall hearing that Swanson had a formula to make early K bells play a specific note without having to machine a bore where the nozzle is.

I need as much information on this topic as possible, I've never really heard anything about this concept.

Thanks!
Brady