Reverse taper

[pt88]

Please can someone explain with a diagram and possibly
the sizes at the various points the difference between


1- symphony shank. Reverse taper (bloke piece)
2 - normal shank eg found on Vb24 DW 2L etc

Found attached after a search but still a bit confused

The Symphony back-bore features an average size throat, but the throat (choke point) is buried well into the back-bore, with what APPEARS TO BE the choke point (at the bottom of the primary cup) being quite large. Thus there is a REVERSE TAPER down to the choke point. Finally, the exit bore is quite large. This back-bore style GREATLY assists in low range response YET (as the choke point is "average" size) withOUT being an "air hog".

[MartyNeilan]

The first picture in my C4 for sale post shows this, as best as can be seen without X-ray vision.

[pt88]

No X - Ray required just a simple sketch to show me what is going on inside the shank