Posted by Rick Denney on January 24, 2001 at 13:47:38:
In Reply to: Re: 4 valve vs compensating euph posted by Chuck(G) on January 23, 2001 at 19:19:50:
And to add to Chuck's answer, the fourth-valve tubing on compensating horns is larger in diameter than the fourth valve on most non-compensators, and this larger bore is carried through the compensation tubing, too. So, when you think about it, a four-valve compensator really is a double horn in Bb and F, though the F side has only three usable valves.
As a tuba player who plays both BBb and F tubas, this feature is most useful to me. Because I can think of the side valve as an button to turn the horn into a tiny F tuba.
It was Stauffer who came up with the notion that a compensator was a double tuba, stating that the EEb tuba could also be considered a double tuba in Eb and BBb.
(Incidentally, Chuck, Stauffer also shows pictures of a York (Master?) double tuba in BBb and F, with two rotary change valves upstream and downstream from the valves, and two complete sets of valve tubing. The front-action pistons were about a foot long, and the bottom change rotary seemed to be about four inches in diameter to maintain conicity. Divide that instrument by two, and you'll have your pure double euph, though the F part would be in f, not F.)
Rick "who thinks 'double tenor tuba in Bb and F' sound really impressive" Denney