Stubbins register mechanism
I hate to put this page under this category. But I want this next to the Mazzeo entry.
Stubbins' register mechanism is perhaps the best attempt to improve the throat tone Bb— which is so notoriously thin sounding. See the resonance fingering page for how most players improve the A and Bb throat tones. I like the Stubbins mechanism because you can use normal resonance fingerings with it.
I am indebted to woodwind.org’s Ralph Katz for this great information:
William H Stubbins was professor of clarinet at the University of Michigan in the 1940's to the early 1970's. His patent was for an improved mechanism for the register vent with an added tone hole just for the throat Bb. This was commercially named the "SK" mechanism. Stephen Fox can make instruments with a similar mechanism.
There is a Noblet Stubbins model listed in this collection:
And best of all, here is another post on this board:
Use the search box at the top right and search for “Stubbins model” and you will find several others reviewed at this site.
Thanks to Gordon Reeves for this article from the Ann Arbor News, November 24, 1967.