5th valve/main tuning slide

[Getzeng50s]

Just curious about what the benifits are to having the 5th valve before the main tuning slide or after it... anyone know?

[Rick Denney]

Just curious about what the benifits are to having the 5th valve before the main tuning slide or after it... anyone know?

I suspect it's just a matter of what works for any particular instrument.

I've heard people complain about the Rusk-style fifth valves in the leadpipe before the first valve, but I've sure played instruments with a fifth before the first that worked just fine. I suspect many opinions on the topic are not motivated by what actually works.

Rick "who has two instruments with fifth valves in front of the first valve" Denney

[Art Hovey]

If you plan to use your 5th valve mostly for the extreme low register, in combination with other valves, then an important consideration is to avoid stuffiness. That means you want a large bore. Placing the 5th valve after the main slide usually accomplishes that. In fact, it would make sense to place the 4th valve there too, although no one is doing that now.

If I ever get my hands on some large used rotary valves and associated tubing I want to try grafting one as a 4th valve onto a 3-piston King (or something similar) and then putting another rotor in the 4th valve tubing as a whole-step 5th valve.
I suspect that arrangement would be freer-blowing in the low register than a conventional small-bore piston tuba. I'd like to see some rotary valve manufacturer produce conversion kits so that all the 3-piston tubas in the world could easily be converted to 4 or 5-valve instruments.

[Getzeng50s]

hmmm i wonder if thats why my horns is stuffy in the low register.. crap

[Rick Denney]

hmmm i wonder if thats why my horns is stuffy in the low register.. crap

Your horn is stuffy in the low register because the bore is small in all the valves, not just the fifth. The vibrations don't know that the tubing they're going through first just happens to belong to the fifth valve.

It's also a matter of nomenclature. On the typical rotary tuba, the fifth valve always comes before the first. It seems to work just fine, even in the low register. But the fifth valve is usually quite short, to it should have no more effect than the first valve on stuffiness.

It makes sense that the longer valves would have a larger bore to compensate for their length. If the fifth comes first, that plan is maintained, if the third and fourth valves have wider bores as they do on my B&S F tuba. And that isn't behind the fuzzy low C on many rotary F's--the fifth valve doesn't even have to exist for that effect to be present.

I can't detect any difference in "stuffiness" between notes fingered with and without the fifth valve on my Yamaha F tuba. That fifth valve is in the leadpipe. For example, the difference in feel between the 4-5 low Bb and the 2-3-4 low A is indestinguishable.

I suppose it's possible to design a 5th valve that would be stuffy anywhere, but it's also possible to design one that isn't.

Rick "who can argue it from all sides, but for whom it still comes down to what works for a particular instrument" Denney