Posted by Henry on March 01, 2004 at 10:50:45:
In Reply to: Physics of Tubas posted by Cook on March 01, 2004 at 09:53:15:
Being a "Mr fix it" type myself I can testify that the closed pipe/ cone harmonics theory doesn't come close to fully predicting the results of a tuba with it's assortment of cylindrical tubing, curves of varied radii and differing rates of conical expansion throughout the horn. The particular aspect of the tubing at the point where the harmonic node aoccurs in the horns body appears to be the dominant variable. This was graphically brought home to me when I upgraded the giant PVC bugle I keep on the floor of the back seat of my Civic. (18 feet of PVC piping doubled back on itself several times- garden hose lead pipe to driver's seat gradually expanding to a 5" pipe for the last two feet). You'd expect that, timbre aside, the thing would play in tune with itself. Not so. Hours of tinkering with joint placement and pipe lengths was needed and the thirds are still way flat. On a far more sophisticated level one has but to stop by any large tuba emporium to discover that the high school physics model is close.... but does not exactly merit a cigar.