3 Valve Compensating Tubas

[tubahero300]

someone please explain how that works, i thought you needed four valves for a compensating system.

[Ulli]

It is the same way, but the 3rd valve activates the compensating system.

IMO works the compensating system with a 3v horn more often than with a 4v.
If I must not play very deep, a 3v comp satisfy me absolutely.

Thats the perception of a BBb and EBb tubist and Boosey& Co enthusiast.

Ulli

[b.williams]

Check this out:

http://www.dwerden.com/comp/aCompIntro6 ... ow_F4.html" target="_blank" target="_blank

[iiipopes]

Yes, Dave Werden's aplet is about the best explanation there is. As far as I know, there have been three 3-v comp tubas: the old 15 inch bell Besson/Boosey Eb, the 17 inch bell .730 bore Besson/Boosey BBb, which I used to own one, and the Hirsbrunner rotary. With mine, it wasn't just theory: except for 1+3 C and 1+2+3 B nat being a tad "stuffy," it had the best intonation pitch-wise of any tuba I've ever played, before or since. Just like F tuba players have "the dent" to get 4th valve C to speak better, mine had "the dent" on the knuckle between the 1st and 2nd valves which kept the 5th partials in perfect tune, and even the high 7th partials I could play top space Gb 1 and G nat 2 with minimal lipping.

Another positive note (pun intended) about a 3-valve comp is that (BBb fingerings) G and D is played 3 alone, not 1+2. This gets them in better tune, because unlike a conventional tuba or a 4-valve comp, you don't have to pull 3 to get 2+3 or 1+3 in tune; the comp loops do that for you, and you don't have to compromise between 1 and 2 each being a tad flat so 1+2 is not so sharp. So you can tune each individual valve "dead," and not worry about the combinations being sharp: the entire raison d'être of the compensating system.

One of these days, if I had the cash, I'd get the Hirsbrunner version, even in spite of the double-decked rotors being the triplene to save weight and improve inertial response. Hey, if I had the cash, I'd even get the valve block from Wilco who converted his 3-valve comp to a 5-valve conventional.

The tradeoff for a 3-valve comp is the absence of a good near-pedal register, because the critical nodes and anti-nodes are in the valve block and don't resonate well for the "false" or "privileged" tones, and the logarithmic taper of the classic 17 inch bell isn't necessarily condusive to the propagation of the necessary final node, but does help the overall intonation otherwise. That is why most folks have gone to a 4-valve comp or a 4- or 5-valve conventional. But for 99%+ of standard concert band literature, it's not needed. Even at that, on the singular occasions I wanted low Eb, I could get it, if I had enough time to set it, by pulling the 3rd valve slide. It was long enough. I always considered putting a dependent rotor in the bow of that 3rd valve slide to trigger an Eb, but for one note it would have cost more for the parts and labor than the entire tuba, plus repairs, cost me when I purchased it.

Epilogue: the Besson is a tank of a tuba, both weight-wise and bracing-wise.