What is a conical bore

We use the term “conical bore” here to describe a few of our popular models (the CV, GH and GA). Let’s go over where it came from, what it is, and what it does.

The concept has been around for a while and is alternatively called a “double cup”, “vortex cup”, “convex”, “Viennese” or a number of other terms. We’re far from the first people to notice the effect, and in fact some early natural horn mouthpieces were even more extreme versions; they didn’t have a back bore and would just be a smooth curve narrowing from the cup down through to the end of the shank.

In more modern times we’re seen it applied on Moosewoods, Hills, PHCs, and even an original Geyer. It’s not universal by any means but it’s a lever many designers have played with before.

 So what is it?  You start with our standard cup design which looks something like an hour glass.

Now you overlay your cone

And you make your cut.

As you can see we’ve expanded the bore area by putting a cone in there - hence “conical bore”. We specify the numbers as “upper diameter” and “lower diameter” - so a #1|#13 like the CV is a 5.8mm base tapering down to a 4.7mm actual “bore”.  

So that’s what it is but what’s it do?  It adds a richness to the sound and enhances the color change from quiet to bright.  They are also more stable (in the stability to responsiveness tradeoff - https://strachan-brass.com/blogs/news/on-stability).

So if you want a warmer, stable mouthpiece with a large color change as the dynamic ramps up, one of our conical bore series might be for you!