TubeNet

davemcrobs wrote:Does this make sense to anyone? In my experience the shank of a tuba mouthpiece does NOT fit directly into the mouthpipe(leadpipe) like a french horn or trombone venturi. Instead there is a reciever that holds the mouthpiece before entering the mouthpipe, just like a trumpet. In my opinion more resistance would be created if the end of the backbore is larger than the opening of the mouthpipe. Opinions?

It depends on the manufacturer. Some do use the leadpipe itself as the receiver; many don't. Where a separate receiver is used, it's usually machined out a bit to accept the end of the leadpipe, so that there's no discontinuity. It's sometimes very difficult to determine which is which by feel alone (using an angled probe).

Given that many tuba leadpipes are oval around the bends (and no one seems to mind) I wouldn't think that the end of the mouthpiece has much of an effect.

Consider, for example, the Monette tuba mouthpieces. Stubby things with short lopped-off shanks. I don't think that they'd sell at all if they performed in an inferior matter compared to, say, a Faxx or Kellyburg.

davemcrobs wrote:Most leadpipes should be round. A hard medium is inside a pipe before you bend it. Usually pitch, a mixture of tar and rosin. Sorry but I can't give away the secret company recipie. THen it is heated to remove. If there is any ovaling that happened during the bend, the pipe can be run through a draw plate to bring back to shape. I have made several horn mouthpipes but no tuba. I think it would be harder considering the larger radius and compound bends.

Dave, I've installed a few leadpipes myself. Both pitch- and cerrobend-filled. I believe some manufacturers also use a mixture of Murphy's Oil Soap and water, frozen to a slurry.

Even with metal filling, a leadpipe will acquire an oval shape, particularly where it wraps around the bell. The remedy, of course, is to take out your draw rings and dent balls and work the thing back round again, but not all makers take this extra step.

Horn leadpipes are easy to keep relatively round. The bend radius is fairly gentle compared to the tube diameter. One rarely even needs to spend much time hammering out ripples on the inner curve. Tuba leadpipes, particularly large-bore rotary ones, take quite a bit of work to get just right unless one has the industrial equipment to form them.

That being said, I'm not sure that it makes a whole lot of difference to response or playing characteristics of a tuba.

davemcrobs wrote:But back to the subject, I don't think this so called thick edge on a shank is creating problems. It's a marketing thing just like Loud claiming SS is denser than brass.

Yeah I think you're right.

It's fun to look inside of some of the old tuba bows and see the hammer marks brought through on the inside, while the outside has been sanded smooth as a baby's bum. And the nasty looking raised brazed seams that lurk under bottom bow caps.

So much of the instrument business, like beauty pageants is only skin deep. A lot of the rest, as you say, is smoke.

BTW, you can still buy 5 gallon buckets of pitch from marine suppliers who cater to the vintage and reproduction crowd. They sell oakum too, but I haven't needed it so far on any of my tuba repairs...

davemcrobs wrote:But back to the subject, I don't think this so called thick edge on a shank is creating problems. It's a marketing thing just like Loud claiming SS is denser than brass.

Seems much more plausible to me. I've read some fairly reasonable sounding things here about turbulence there, and it makes intuitive sense that turbulence would be more of an issue at the mouthpiece end than out towards the bell.

Of course "intuitive" is about the same as "ignorant", but the other nice thing about the shank end hypothesis is that, unlike material density, it might be pretty trivial to get experimental evidence. If you're sure the shank end doesn't matter, then you won't mind messing around with it a little for the sake of science.

The most interesting thing I've read recently in tuba mouthpiece science, was the theorizing about rim surfaces. What I got from it was that especially during loud playing, there can be some movement across the rim, of course depending on the material and how well it sticks. So they're (G&W) trying out textured surfaces, which is new, but the theory could account for some of the differences between materials like stainless steel, silver plate and Lexan. I think G&W deserve credit for this kind of continued exploration of how mouthpieces work - and if they say the shank end matters, I'd be inclined to take their word for it until proven otherwise.

davemcrobs wrote:

Seems much more plausible to me. I've read some fairly reasonable sounding things here about turbulence there, and it makes intuitive sense that turbulence would be more of an issue at the mouthpiece end than out towards the bell.

Right, So what happens when the end of the mouthpiece is bigger than the opening of the mouthpipe? Wouldnt that create turbulence?

Sure, and "intuitively", your idea that it would increase resistance sounds right.

I will make a note to look inside my receivers, maybe they are noticeably wider than the leadpipe. Never noticed that before, though, and if Chuck says they're usually set up to match the leadpipe ID without discontinuity, that sounds right to me.

davemcrobs wrote:Right, So what happens when the end of the mouthpiece is bigger than the opening of the mouthpipe? Wouldnt that create turbulence?

Maybe, but I don't know if it's even germane to playing characteristics. The rate of flow and the velocity of the airstream through a tuba is extremely low--it's hard to see how anything but a major restriction would have an effect.

That transition between the end of the mouthpiece and the receiver (or leadpipe) could cause a change in the way a horn plays. The key word here is COULD.

More often than not, the mouthpiece end is going to terminate inside the receiver... NOT inside the leadpipe. The generic receive I use for most replacements is a Conn design. The end where the leadpipe is inserted for soldering is about .590" diameter. Leadpipes have a wall thickness of about .025". That gives a net diameter INSIDE the leadpipe of about .540". The small end of the dozen or so tuba mouthpieces I have laying around ranges from .516" to .530" on the outside of the small end. Not only does the 'step' between the size of the diameters change... the 'gap' also changes depending on how far the mouthpiece goes into the receiver. This 'gap' is yet another discussion. Anyway.... until mouthpiece manufacturers develop an exact size for the end of their shanks it's not going to make much difference.

How much does all of this affect how a tuba plays? Who knows! Until some attempt is made to get rid of some of the variables there's not going to be a good answer other than saying 'everything makes a difference'. The question remains though... is the difference good or bad?... and is it the same for everyone?

The biggest difference is the person playing the horn! And I'm not talking about ability. I'm speaking of physical characteristics like sinus cavities, bone structure, oral cavity, etc.. The true test is what works for you.

Quit searching for the Holy Grail. Now... go practice!

And if you buy a tuba from this guy, you should know what to expect:

http://reviews.ebay.com/How-To-Install- ... 0002567861

TubaTinker wrote:... until mouthpiece manufacturers develop an exact size for the end of their shanks it's not going to make much difference.

And I would respectfully submit, that until TUBA manufactures develop an exact size for their receivers...


Thank goodness for Matt Walters!
MF

Mike Finn wrote:

TubaTinker wrote:... until mouthpiece manufacturers develop an exact size for the end of their shanks it's not going to make much difference.

And I would respectfully submit, that until TUBA manufactures develop an exact size for their receivers...


Thank goodness for Matt Walters!
MF

There is truth in what you say. However, I submit that I have a dozen different mouthpieces with a dozen different shank dimensions. Where I'm going here is that what tuba players often perceive as a mouthpiece cup shape making a difference in how their horns sounds might actually be how the taper fits the receiver.

Mike Finn wrote:
Thank goodness for Matt Walters!
MF

I love my horn's AGR!!!

KevinMadden wrote:

Mike Finn wrote:
Thank goodness for Matt Walters!
MF

I love my horn's AGR!!!

Then you should thank goodness for Steve Dillon. He holds the patent on it.

KevinMadden wrote:

Mike Finn wrote:
Thank goodness for Matt Walters!
MF

I love my horn's AGR!!!

...just for the sake of clarity, I was referring to the post by Matt Walters describing (defining) the various shank sizes. I'm sure I'm not the only one here who copy/pasted it to a Word document for future reference. Anyone got a link? There was even talk of making it a permanent addition somewhere, maybe in the tips section.

MF

What is the consensus regarding the optimum mouthpiece/receiver gap for a tuba?

Pop Korn wrote:Blow smoke gently into a bass. Play for as long as it takes for the smoke to come out. That's how fast air moves through..

How does one play and blow smoke through a bass at the same time?



...and even though I said pretty much the same thing, I can appreciate the original question. The end of the mouthpiece isn't far from the throat--and changes to the throat can have a significant effect on playing characteristics, as can things such as leadpipe taper.

Pop Korn wrote:Now very little air goes through any brass instrument.

Relative to the volume of the tuba, that's sure true, but relative to our puny lungs it can seem like a lot sometimes. At the narrow end, it isn't obvious that the air flow is insignificant.