Unquestioned tuba design choices

[joh_tuba]

Just like Bloke's recent Rudy mouthpipe experiment I wonder what other 'opportunities' for learning by trial and error might exist.

Specific examples:
1) The MAW valve seems like a definite step forward. Kanstul has an interesting rotary valve design. Perhaps someone else will come up with something better still regarding valve design. Note: All MW/B&S rotors squish the bore to 16mm no matter the size of the pipe going in and out of it. Willson Rotax rotors do the same to a marginally lesser extent. Miraphone generally squishes to about 16mm although I think they've recently experimented with a larger body rotor. Not measured a Rudy rotor recently but I suspect they squish the bore even more. I'm sure this was a conscious design compromise perhaps to keep the valves light and fast.
2) Interchangeable pipes is not a new idea but doesn't seem to be offered as much as it used to be. I wonder if a few popular/trendy tubas could be readily improved with a new pipe.
3) Along the same lines are reciever 'gaps'. AGRs are an old idea with 'some' use on some horns. Also, receiver sizes on same make and model tubas have changed over time with no commentary from the manufacturers. More specifically, I've come to wonder why the current German made Bessons have a *marked* drop off into the mouthpipe(essentially doubling the size of the step coming out of the tip of the mouthpiece) where as other Buffet Group tubas have a smooth transition into the pipe. My pet theory is that it puts the turbulence at the mouthpiece so that there's less of a perception of unevenness when blowing through all the bends in the compensating valve.

Definitely not looking for anything in particular.. just pondering thoughts and seeking random observations.

[joh_tuba]

Greenhoe is nice..is it much different from the Kanstul? There's also Haagman, and Bach K valve and probably a dozen others I don't know about. Upscaling those ideas to tuba bore sizes might create another set of issues.. but it would be fun to see someone try!

[joh_tuba]

The standard rotor body is about 34mm in diameter.

http://www.millervalve.com/tech.html
Miller valve looks similar to the Bach K valve and might be a more logical alternative to the Kanstul rotor. Maybe someone would commission a tuba sized valve section from them.

I'm personally skeptical that we need to go the direction of trombone with their million valve options.. it could get silly pretty quickly.. but if something is better, why not?

Quite a while back I took the rotors of my personal horns to a belt sander to remove that extra bit of brass that seriously serves no discernible purpose. I did this to a PT6 and a PT15. Both horns were improved by this modification with no negative ramifications. None. In fact, not only do both horns play more like I want them too, the valves are also faster and lighter now.

[bububassboner]

There are a lot of different design features that to me seem silly. This is the reason why I am studying brass building. With these skills I can attempt to make a better tuba. That's why I buy old horn parts. So if you some hit me up.

[joh_tuba]

http://www.bias.at/?page_id=8&sprache=2

Would be fun/interesting to own this bit of kit and plug horns into it all day. Pretty confident the major manufacturers use this or a similar product during the design process but a boutique horn builder/high end repair shop could use it to analyze problem instruments.

Who wants to buy it for me? Thanks!

[joh_tuba]

Having spent too much time staring at the B&S/MW rotor bodies I can tell you that while all of them squish the bore to 16mm, the larger the bore the more they are ever so slightly elongated(taller). It's definitely not enough to make up for lost volume... but it's something. In thinking about these things WAAY too much I think the primary reason that rotors larger than 22mm aren't commonly produced is because of this elongation process. A 21mm rotor body cutout is already quickly approach the max height that the rotor body will accept. They would need to further compromise the bore OR retool both the body and the casing to maintain their current design parameters for elongating the port.

From the factory the body cutouts are a bit of a sideways 'C' shape. I've turned mine into a sideways 'U' shape by removing the seemingly unnecessary extra bit of brass.

My personal opinion(based on not much and subject to error) is that this modification can't possibly hurt how a horn plays for the following reasons:
1) the bore is already distorted, how can I mess up something that's already jacked?
2)it reduces mass
3)it conserves volume closer to that of a straight pipe
4)the removed bit of brass needlessly ocludes the valve ports during transit, removing this occlusion seems to make things 'snap' into place better during transitions

This change, to my mind, isn't all that different from what's been done to pistons with the MAW valve. Martin Wilke increased volume where there was an obvious distortion, removed an occlusion of the port during transit, and reduced weight.

[Mikelynch]

I will add a few comments on the Allen valves. I have one horn with them, and have had the opportunity to play 4 others. In 2 cases I was able to compare them directly with an essentially identical horn with conventional rotary valves. In all cases the Allen-valved horn played extremely well, and in the comparisons played much better to me.

Of course, these weren't comparing a 186 to a 186 with Allen valves. These were all 19th century tubas, all Eb's (on which I claim absolutely no prowess). But as counter intuitive as it seemed to me, given that the rotor diameter is somewhere in range of .500-.600 (or so), and the tubes were (seemingly to me) extremely ovalized, I have really liked every Allen valve horn I have played-a lot!

I would love to see a modern day evaluation of them (and it's quite possible they don't scale well to a .780 to .810 or bore). But at least in their time, they worked well on the smaller tubas.

Mike

[ralphbsz]

Question from a clueless person (I'm purely a keyboard person, and only the dad of a budding tuba player): Why not use whatever valve has the straightest air flow, and make it really large, so large that the bore diameter of the pipes is not constricted in the valve. OK, so you say that the valve will be too large to move fast enough. But that's only because we only have the power of one human finger to operate it.

So how about taking that impractically large valve, and operating it electrically? With a reasonable energy source (rechargeable battery) and a few solenoids or fast motors, it should be possible to move even a very large valve very quickly and accurately. Instead of valve buttons or paddles, we would have an arrangement of switches.

The obvious concern is: Does this lose the "touch" ??? Do tuba players actually deliberately press the valves partially or slowly? I know about the horse whinny sound (at the end of "sleigh ride" for example), which requires half-pressed piston valves on the trumpets. But other than those few special effects, would really fast electric valves be a good or a bad thing?

There are also "minor" engineering issues (like where to find room for these much larger valves, and the battery and the electronics, and how to make the whole mess reliable and affordable), but those should be solvable by smart engineers.

This is a little bit like the pipe organ (which is a wind instrument I have actually played): On many mechanical-linkage organs, some registers (like couplers between manuals or couplers to the pedal) are implemented electrically, because the total amount of force that would be required to operate this many valves is impractical. And while early on, serious organists disliked organs with completely electric linkage, they seem to be coming around. It seems that on the organ, "touch" is very overrated, and in practice organists just press the keys all the way down quickly anyhow.

By the way, there are some high-end target shooting pistols that use electronic triggers, for better accuracy and repeatability. They still have a traditional trigger lever, but it only operates a microswitch.

If this is complete nonsense, just ignore me.

[Eflatdoubler]

I have the Greenhoe valve on my tenor and bass trombones and really like them. I believe they are made from a solid piece of metal where as the Kanstul valves are machined out of two seperate pieces. I haven't played a Kanstul rotary valve in a while, but I thought it too was a good valve. Frankly, what I like most about my Greenhoe valve is the short throw, and also the cut-out outer cap which allows the horn to resonate in a more pleasing way to my ear. The valve section is also braced in a way that nothing contacts the bell. I have had Edwards trombones with a Thayer valve with edge bracing, and a Bach with a Thayer installed in a similar fashion, but the efficiency of both horns that I converted from Thayer valves to Greenhoe valves was a vast improvement for me.

I had tried the Bach K valve when it first came out. It is a good playing valve, although its size can make it akward to play as it can be a bit uncomfortable against your neck, depending on the phsyiology of the player.

I had heard great things about the Miller valve when it first came out. I often wondered what became of this valve design. There were rumours that it would seize up too frequently, but I never had any actual experience with one...

[NCSUSousa]

So how about taking that impractically large valve, and operating it electrically? With a reasonable energy source (rechargeable battery) and a few solenoids or fast motors, it should be possible to move even a very large valve very quickly and accurately. Instead of valve buttons or paddles, we would have an arrangement of switches.

The obvious concern is: Does this lose the "touch" ??? Do tuba players actually deliberately press the valves partially or slowly? I know about the horse whinny sound (at the end of "sleigh ride" for example), which requires half-pressed piston valves on the trumpets. But other than those few special effects, would really fast electric valves be a good or a bad thing?

Interesting idea. I know I'd like a faster moving valve that also flows better. Easier operation will be a huge benefit (vs using stiffer springs).
Having really fast valves using motors for operation would be great as long as the brass can take the stress. It may require that the entire valve section is made out of another (stronger) material to withstand that amount of impulse every time the valve is moved. Then the only other question is overall weight.

A fast electronic open/closed system should work for most players. I know there are some instances where the partially depressed valve is used to achieve special sounds in solo tuba playing. It should be possible to add an upgraded control board for advanced players that would allow 3 positions on the solenoid system - open, '1/2' and closed. I'm not sure 50% of the rotation is the right point for that so it may need to be adjustable.

[Donn]

Interesting idea. I know I'd like a faster moving valve that also flows better. Easier operation will be a huge benefit (vs using stiffer springs).

Also more flexible. Put the buttons wherever, close together as you want. I've seen buttons that were like a short magnet in a collar, so rather than on/off, they translate movement to an analogue signal. Which you could use to drive the piston - so in effect the same kind of control as the normal valve, but via an electro-magnetic linkage that brings in battery powered amplification of your fingers' movements.

[pjv]

Isn't one of the selling points of the Shires Rotary valve that the valve retains the same bore size as the horn itself?

http://www.seshires.com/valves.html" target="_blank

[Jose the tuba player]

The stealth tuba didn't cost much to develop.

so when you going to start mass production


well why not just use both rotors and pistons like this?
http://www.youtube.com/watch?v=q3pEpk_4JZg" target="_blank

[joh_tuba]

New thought: Is there any practical reason, other than tradition, that the leadpipe wraps around the bell side of the body? On many/most horns it blocks one eye from seeing music/conductor.

Without giving this much thought, seems like flipping things around wouldn't hurt anything. Also, particularly in a quintet setting it would be nice to have an unobstructed view to the player on your left.

[pjv]

Like on a Tornister. Ha ha, I've often wonder this myself. It wouldn't be such a bad thing to be a little less under the bell and a little more in closer to what's coming out. There are some examples of tubas like this in the early tuba history.

Tuba design; the perfection of a detachable mouthpipe. I've had many mouthpipes moved by tech's because I play with my mpc at a downward angle (more than most players?). The techs usually loosen the pipe at the valves, rotate it a little and then readjust the bell-mouthpipe brace. This works quite easily on many non-german style tubas.

If the seal from the mouthpipe to the 1st valve could be guaranteed to near perfection, an adjustable bell-mouthpipe brace would only be a detail. Unfortunately the technology/interest in this isn't enough to make it standard. I guess the sousaphone neck design (or tbn bell to slide lock) isn't good enough for tubas.

[MaryAnn]

Are we talking solid rotors or hollow rotors?
MA