Homespun Acoustical Theories

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Posted by Joe S. on May 10, 1999 at 23:22:11:

Well, here's another one. After junking around with Frankensteining and repairing tubas (and then playing the dern things!) for quite some time now, I have developed some theories which may or may not be of any merit:

I am starting to believe that

1/ Tubas that have bells and bottom bows that are VERY large in proportion to the other smaller conical branches of the tuba end up with some sort of sagging third* partial problems. These problems will almost always be there under these circumstances, but may vary as to which notes are effected the most, depending on the particular taper of the smaller branches.

2/ Tubas that have very LARGE smaller branches in relation to the size of the bell and the bottom bow (particularly the bow and lower bell), will have problems with the sixth* partial notes being sharp. Again, "which" sixth partial notes are effected and how much depends on the particular taper of the smaller branches. These tubas usually seem to blow quite "free", regardless of the bore of the valveset.

3/ Tubas that have more predictable ("standard") proportions between the smaller conical branches and the bell/bottom bow will usually have the least intonation problems, but also tend to offer a little more resistance when they are played.

4/ The bell flair itself has very little to do with intonation, but has a tremendous amount to do with the tone quality of the instrument.

*For those of you in Tupelo, Mississippi, 3rd partial notes are bottom line G down to (actually further, but in this reference) around Eb for the CC tuba, and the neighbor F down to Db for BBb tuba. 6th partial notes are an octave higher than 3rd partial notes, but only would include G-Gb-F for the CC and F-E-Eb for the BBb. (OK, maybe for those of you in West Memphis, Arkansas, too)

I think that is as far as I will go with my wild ideas. Would anyone be willing to refute/support any of my theories, or support any of them with exceptions, amplifications, or qualifications?

Have fun with this,


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