Graduated Bore

[chronolith]

There is plenty of stats from manufacturers about the changes in bore on instruments.

Are there occasions when a manufacturer has made a design mistake and graduated the bore too quickly? How does this manifest in the horn response? Can it be addressed without redesign?

[iiipopes]

If the bore expands too quickly, it will result in flat notes where the anti-node coincides with the expansion of bore. there really is no fix other than alternate fingerings, if possible, unless you want to completely rebuild the bow that is expanding too quickly. Holton 345 3rd partials having to be played 1+3 instead of open come to mind. The joint on my 'glass souzy needs to be rebuilt, because, of all notes, its expansion through the joint from the brass to the 'glass is right on anti-node of the tuning note 2nd line Bb. Hopefully, a little redoing of the O-ring will be all that is necessary, otherwise it's lengthen one and shorten the other, either way, to get the joint off the anti-node. But then if you go the wrong way and the wrong amount, other notes' intonation characteristics could get fouled up in the process. So it is not an easy fix. With a new neck and pair of bits, I only have a few hundred dollars in my souzy, so I'm not going to be spending much more than a roll of tape, a $1.79 O-ring and a new tube of slide grease to "fix" it, as it is very lippable.

[Three Valves]

I was a Bore even before I graduated!!

[Tubajug]

How do you find out where the antinodes are, and is it something you really need to know? I'm curious.

[iiipopes]

Run your finger lightly along the bugle as you play a given note. The places where you can feel the vibrations are usually the anti-nodes. Another way to show what effect they have is to play various notes, and while holding a note, open the water key. If the water key is in a node, it will have practically no effect on the note. As you play notes with different speaking lengths and you approach a note where the anti-node is in the same place, when you open the water key, intonation will change dramatically, and sometimes the note will cease to speak and crack hard.