What tuba is this?

[rocksanddirt]

Is the title of this thread also the title of a Christmas song? If it isn't, it probably should be.

What tuba is this?
Which laid to rest
In my den is keeping....

Well, I guess I need to work on the words a bit.

Ha! i did the same when i saw the title....

[rocksanddirt]

'snip'
But for the "cash register," two octaves between low 4th valve 4th ledger line F up to 4th line open F, the only note that really needs adjustment is midline D takes 12 instead of open, 2nd valve Db needs just a hair of lip up, 1st ledger line Eb takes a little bit of focus occasionally if the rotors are dry, and everything else is set and forget.

This is generally my experience of an older narrow bell 186 (16 1/2" or so). It plays well intune with itself and others in the range where 90% of playing is done.

[sloan]

c) instead, it seems that we can identify the "false tone" with the actual first partial. Notice that buzzing 0.7 f0 will access this partial - but the note should suffer from
a LACK of supporting higher harmonics. Where will the {1.4, 2.1, 2.8, 3.5, 4.2,...} f0
come from?

I don't think that 0.7 f0 is the "false tone" of most tubas... 0.7 f0 is, by definition, a lower frequency than the pedal tone f0, and would therefore be a lower pitch... if you take that 0.7 and "un-round" it to .75, you get a note a perfect fourth lower, which seems to me more like the open pedal G one can get on a trumpet. A tuba's false tone a perfect fourth *higher* than the pedal tone would actually be 4/3 f0... beats me where that fits into the series of partials.

Right you are - my mistake. You demonstrate the importance of actually *doing* the arithmetic.

Here's an interesting idea (from Wikipedia - approach with caution):


"The most convincing explanation for false-tones is that the horn is acting as a 'third of a pipe' rather than as a half-pipe. The bell remains an anti-node, but there would then be a node 1/3 of the way back to the mouthpiece. If so, it seems that the fundamental would be missing entirely, and would only be inferred from the overtones. However, the node and the anit-node collide in the same spot and cancel out the fundamental."

Another thought: 0.7f0 is close to 1/2 of (4/3)f0.

A weakness in both ideas above is the appeal to "a pipe". A tuba is not a pipe. As usual, reasoning by analogy to a simple pipe (or string) gets you tantalizingly close
to the right conclusions - but it seems to me that this speaks more to the skill of the designers who produced tubas that almost produce a "harmonic series" than it does to the correctness of the reasoning.

The point (alluded to by previous posters) may be that the designers care a LOT about making the tuba act like a string in the "cash register" and feel free to push the deviations from a pure harmonic series out into the frontier, where only the strong and the brave dare venture.

I am reminded of the task of aligning old fashioned CRT monitors. Expensive ones often had a pull-out tray filled with an array of potentiometers. Getting the alignment perfect everywhere was damn near impossible - but it was often possible to take the problems and push them off into the corners. One could then tell the users to stay in the middle of the screen.