Posted by Rick Denney on June 14, 2002 at 14:48:51:
In Reply to: Bore sizes and other measurements... posted by InkyDaveB on June 14, 2002 at 14:02:46:
Tuba makers try to give you a notion of how big an instrument is, using whatever can be measured directly. One of the least useful, in my view, is bore size, which is the inside diameter of the valve tubing at the second valve (usually in inches, but sometimes in millimeters). I'm not sure there's much correlation between bore size and the application of an instrument. Rotary tubas tend to have larger bores because rotary valves are easier to build with larger bores and because the valves are farther along in the tubing of the instrument where it is fatter.
Bell size also has a subtle effect. Bell shape is more important. The modern trend is to larger bells, which widens the dispersion of sound and makes the instrument easier for the player to hear. Typical full-sized BBb rotary tubas have 17-inch bells, and typical piston tubas have 20-inch bells, with considerable variation in each category. Excellent tubas can be found in all categories. The rotary tubas have a little different sound concept than the piston tubas, and the bell sizes are part of that formula, but these two broad categories are still more similar than different.
To me, the overall size of the instrument has a bigger effect on its application to given performance situations, but even there generalizations are misleading. To give you an idea of different tuba sizes, take a look at the link below, though it doesn't include many rotary instruments. You'll want instruments in the 4/4 category.
Rick "wondering if Dave can play tubas at Low Brass Werks despite Tony's absense" Denney