Posted by Gerald J. on August 17, 2001 at 13:21:27:
In Reply to: Vibration, damping, and weight posted by Rick Denney on August 17, 2001 at 11:26:02:
All this is made much more complex by the differences in stiffness and in damping for ALL the brass pieces of the horn which depends on the degree of work hardening since that last anneal. Annealed brass and copper has the resonance and stiffness of sheet lead, while work hardened brass begins to make a passable gong. That's how cymbals and gongs are made, a great deal of work hardening by hammering after spinning. Its likely that one of the huge variables in construction is when the instrument maker decides to anneal the part. Does he sometimes do one more bend before annealing, so that sometimes the finished piece has more or fewer working steps after the last anneal? I suspect so and that along with the variable sizes of solder blobs in small passages to change their geometry is what makes horns be highly variable on the showroom. Perhaps to make construction easier the St. Petes anneal more often than other makers or just do very little work on other metal parts after the last anneal and so end up with soft metal to make them easily bent.
Perhaps, just perhaps, sometimes a brass horn that's resurrected from many dents is improved by the work hardening involved in removing bocoup dents. But if the shop finds the creases won't go without annealing then the horn is made more mellow from the relative softness of the annealed brass. At least more mellow where that part is at a pressure peak for a specific note or group of notes.
I think the state of the work hardening of the metal is more important than the leather belt, the valve cap weights and the mouthpiece weights. And that we players have the least control over that work hardening.
Gerald J.