Re: Re: Re: Taper and intonation


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Posted by Ken Herrick on October 27, 2001 at 03:20:13:

In Reply to: Re: Re: Taper and intonation posted by Art H on October 26, 2001 at 23:16:55:

Yes, Art, Ren was a trumpet man but had a very good knowledge of brass instrument desing in general. I got to know him and his work prettu well over a period of years and spent some time working for him. While we are here, I might as well point out that Ren designed a full line of instruments for Yamaha late 60s - early 70s, including tubas which initially were based on Boosey & Hawkes / Besson. I spent a fair amount of time playing on the first Yamaha CC prototype (a cut BBb)during my lunch breaks back in 70.

Your comparison of a tuba lead pipe to a trumpet mp backbore might be fairly close in terms of length for some of the instruments using the short "straight in" types. Considering a trumpet mp backbore would be about 2 1/2 inches (A tuba mp being fairly near the same) we would be looking at a roughly 7 1/2in leadpipe being the equivalent.
I have not seen any tubas with that short a lead pipe.

My purpose here is not to be argumentative, but to consider design parameters. I studied this area a fair bit with Ren, Jake, the horn maker Carl Geyer and others and am convinced that the section of tubing with which one may most effectively effect intonation is the lead pipe.

One might wonder, after reading the Schilke article, whether the short lead pipe is
the best approach if one wants to fine tune the inherent intonation of a tuba. If you look at the usual German approach the lead pipe is quite long. Possibly if makers spent as much effort in designing this part as Ren did, we might have more tubas which played better tuning wise. The Accoustic principles are the same for a tuba as a trumpet.

One problem we have is that tuba leadpipes are bent which makes it much more difficult to control inner diameters at many different points. If we used a straight pipe it would be a lot easier. When Fred Marzan was dedigning his line of tubas he did a lot of work using straight instruments. It would be somewhat easier to maintain close tolerances on a lead pipe than on the after valve body branches.

In the end of course, any brass instrument is built incorporating many compromises and this is very much the case on such a large instrument as a tuba.


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