Re: Re: Re: Re: Re: Re: OK, I did it - update


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Posted by Jay Bertolet on October 20, 2001 at 08:31:52:

In Reply to: Re: Re: Re: Re: Re: OK, I did it - update posted by js on October 20, 2001 at 01:08:23:

This is one of those times when I sincerely regret being a tuba performance major and not an english major. I've never been able to write (compose) very well and I could use a good wordsmith about now. You said exactly what I was trying to say only much better.

It is indeed the vibration of the column of air that defines our sound. A tuba is a convenient enclosure for that column. But the tuba has an effect on the column as part of the process of enclosing it. As the column vibrates so does the tuba, to a degree commensurate with the general construction of the instrument (placement of posts, thickness of metal, size of bell, etc.). Obviously, there are many variables that effect this vibration of the actual instrument. I look at it like any system that can be inefficient. There are always places where the energy put into the system is dissipated in ways other than the final product. Any lessening of that energy loss makes the system more efficient and has a result on the final product. If we eliminate the inefficiency of sympathetic vibration loss in a tuba, what happens to that energy? We know, from the laws of conservation of energy, that this energy doesn't simply vanish. I don't believe, as you have suggested, that this energy makes another part of the system experience sympathetic vibration more. I believe that the energy that is put back into the system could have one of two profound effects: it could allow for more sound to be projected from the system or it could allow for less effort to be expended in the production of the same amount of sound. Both of these outcomes would be desirable.

In the case of the mouthpiece, I simply don't know enough math to prove what I'm thinking or even to articulate it correctly. However, I would say that we know that dents in a tuba can effect the intonation in the instrument. We also know (through all too graphic empirical study) that dents in the leadpipe can be the most damaging to the playing characteristics of a tuba. Perhaps there is something about the mouthpiece and mouthpipe of a tuba that amplifies the effects of any change to that area of the system? Like I said, I don't know enough math or acoustical design theory to prove what I suspect.

Like I said before, I'm still working on arranging a true apples-to-apples test with a standard R&S Conn-Helleberg copy so that I can record the results and put it through a spectrograph on my computer. Hopefully, this will prove the differences between the two sounds. This discussion has made me very curious to see the results.

My opinion for what it's worth...


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