Hi all. Sorry í don´t speak good English

I work of booth manners, empirics and theoricals. Too by trial, be right and error by obtain aftereffect. I believe, that a combination of all manners (theorics and empirics) is the correct form to be good for anything. Not always the things happen how one want or presume. 

(Relative to that, please Dr. continue with us!! you are very neccesary here!)

1- I ask. If the constriction is the diference between neck tip bore and
the mouthpiece bore shank, that is about a step between them, isn´t it?

2- I ask. That step be must to be prolonged or abated indoor mouthpiece bore? that not is clear because not there are draw of that item.

That step (or constrictión?)i reduce indoor tip of the neck. Beveling the that step indoor tip of neck. Approximate 10 mms indoor the neck i start the beveling similar at this form=  (wall exterior of neck) |\ indoor /| (wall exterior of neck) Do you undestand me? |\ /| (tip of neck corrected with a beveling step)

Fraternally yours

Silverio
3- This topic, can have influence on the low pitch, ex: Bb, B, C, C# notes on alto?