Discussion of tuba sizing

[lost]

Jonathan was trying to make sense of what companies were already doing by sizing tubas. He didn't invent it, and yes it isn't perfect, but it is probably accurate 85 percent of the time from the many many tubas I have had the privilege of collecting as an unapologetic collector.

It's also better than filling up your tuba with beer, water, or whatever.

[Three Valves]

....It's also better than filling up your tuba with beer, water, or whatever.

Oh yeah?? Says who??

[donn]

Why not measure from the end of the bell but from the center point straight down by the same amount on both tubas then measure the bell circumference at that point. In my mind I’m thinking 18” on a B flat vs 16” on a C tuba since we know C tubas tend to have a faster expansion rate.

That's about what I did to compare a couple large tubas. For me, the most interesting dimension is more or less as lost proposes around the beginning of this thread, the small end of the bell or the large end of the bottom bow, but it's more important to take that measurement at a consistent depth, as opposed to the actual location of that joint, as that's quite variable.

Here we're measuring the "bugle" size at a point where I'm guessing it's a product of relatively consistent, regular albeit exponential geometry. Once we get to the bell, the geometry may visibly change - some bells appear to switch to a sort of widened cone, others may taper out more gradually - and while this may have a huge influence on the volume - in air, water, beer, ping pong balls or whatever - I'm guessing it isn't so dominant an influence on tone.

However, a couple doubts, as I mentioned earlier, essentially about getting that depth consistent down to less than an inch -

1. Where do I measure to find that reference spot on my Holton 109 - a bell front tuba? Eyeball estimation of a center line?
2. The end of the tuba's air column, I'm sure I've read, is some ways past the physical bell - and the difference varies, affected by bell and bell flare geometry. Presumably the ideal point of measurement would take that into account.

So ... I don't know, might be ideal to combine an axis measurement with a measurement along the bell surface, and make some kind of a weighted average.

[KingTuba1241X]

sorry...no charts/graphs/numbers (and I respect and am fascinated by them)...but (only relying on observations, memory, personal anecdotal, and the like...)

If an ancient Conn 36J is a "grand orchestral" (yes...?? no...??) tuba (am I wrong, that this was the first tuba with that sort of designation...?? ...and - yes - I could easily be wrong), The Rudy 5/4 tubas' bell shapes seem (to me) to mimic some of those old Conn (non-detachable...and NOT the 25J bells that some stick on the recording version 36J) bells. Further, the Cerveny 601 tubas (which were bought by some - often due to their pricing) seemed more like double-oversize-bore rotary valvesets stuck on Holton/York/etc. 6/4/lap-sousaphone-shaped bugles/bells. With this, too, I'm willing to be shown that I'm wrong...so I wouldn't really put either the Rudy 5/4 B-flat nor the Cerveny 601 B-flat quite into the "kaiser" category, BECAUSE...

...I have a bit of a stricter concept of "kaiser" in my head...The two pictured in my last post qualify (and they must be B-flat tubas), the Meinl-Weston 197 certainly qualifies (well: duh) and others that are close to that shape/size/height...and I believe the somewhat towering height is part of the definition, because (just as with the stubby height of the lap sousaphones - mostly in C) the distance from the tuba's opening to the player's ears (ie. how a tuba is heard by its operator) has definite effects on how a player reacts to their instrument...and the other characteristic (as Rick points towards) is their NOT-sousaphone-bell-shaped bell throats.

' no need to argue these points...They're just MY personal concepts of "kaiser" (B-flat), and no one's else.

Two valid points.
MW calls the 197 a 5/4 and likewise Cerveny did call the 601 a 5/4.
When you see the Mira Hagen in a line the difference between 4 and 5 seems smaller then between 5 and 6.

https://www.pinterest.com/pin/384987468131876226/

The Hagen is a compact Mira 90 it seems, so does the 497 still sounds like a kaiser. Maybe in the hall but not for the player?

So you mean to tell me that both of THESE 2 horns are 6/4 size? Because we know the York Lap Sousaphone on the right is a 6/4.

[LeMark]

Unrelated point... kind of.

When I first started playing a 601 back in the late 80's, I was told it was a special purpose tuba, too large to be used as an everyday, do-it-all horn.

Here 30 years later, there are a LOT of 5/4, do-it-all tubas that people use every day that are just about the same size

[bloke]

Here’s $5 for bloke, just because he's so great.

Well...Thanks...I actually can use that, right now, during these Orwellian times, but: back to the discussion.

I would just like for you to see how I pulled together all of my artistic and technical skills to photoshop Jake's Holton knock-off of his York into a Meinl-Weston 197:

bloke "game...set...match"

[JeffT96]

Why not measure from the end of the bell but from the center point straight down by the same amount on both tubas then measure the bell circumference at that point. In my mind I’m thinking 18” on a B flat vs 16” on a C tuba since we know C tubas tend to have a faster expansion rate.

That's about what I did to compare a couple large tubas. For me, the most interesting dimension is more or less as lost proposes around the beginning of this thread, the small end of the bell or the large end of the bottom bow, but it's more important to take that measurement at a consistent depth, as opposed to the actual location of that joint, as that's quite variable.

Here we're measuring the "bugle" size at a point where I'm guessing it's a product of relatively consistent, regular albeit exponential geometry. Once we get to the bell, the geometry may visibly change - some bells appear to switch to a sort of widened cone, others may taper out more gradually - and while this may have a huge influence on the volume - in air, water, beer, ping pong balls or whatever - I'm guessing it isn't so dominant an influence on tone.

However, a couple doubts, as I mentioned earlier, essentially about getting that depth consistent down to less than an inch -

1. Where do I measure to find that reference spot on my Holton 109 - a bell front tuba? Eyeball estimation of a center line?
2. The end of the tuba's air column, I'm sure I've read, is some ways past the physical bell - and the difference varies, affected by bell and bell flare geometry. Presumably the ideal point of measurement would take that into account.

So ... I don't know, might be ideal to combine an axis measurement with a measurement along the bell surface, and make some kind of a weighted average.

I see what you mean. Anything bell front would be an outlier for sure. I guess measuring at only one point in the bugle’s taper is likely to prove arbitrary with tons of outliers. I do think the liquid volume test would be useful and pretty accurate. It seems like the manufacturers could do that and use it in advertising if they had the will to do so. Maybe leaving things subjective and somewhat arbitrary adds to a “mystique” that certain tubas have from an advertising standpoint?

[KingTuba1241X]

Don't understand your question and I don't know the 2 tubas in your picture.

That's true 6/4 Rudy and a 6/4 American style..

[donn]

Filling with water from tuning slide to bell is the easiest way to measure the volume.
And it is going to be rather accurate since water isn't bother with the shape of the tubing being conical, hyperbolic...

It measures the volume accurately, but so what? Does a unit of volume in the bell have the same acoustic effect, as the same unit of volume in the bottom bow? There's many times more volume in the bell, than in an equal length of the largest branch tubing, so volume really ends up measuring how big the bell is. Looks to me for example like the YBB 621 has a relatively large bell, for its size - so its volume would be deceptively large, for a small tuba. But arguably that isn't really what makes a tuba play big.

[donn]

So from my example of a bell volume of 20 to 25 liters the extra volume can be something around 10 liters maximum.
A Conn 2Xj has a very larger bell but it opens up very late so the extra volume isn't going to be that big.

Yes, that's how the 2XJ looks to me, too, compared to a Holton - two indisputably big tubas, but the 21J bell is a little more slender towards the bottom.

And no doubt it has some influence on the sound, but ... suppose we had a third tuba, with the Holton's bell and the Conn's volume. OK, evidently the difference in volume comes from the branches. I don't know how much difference, but say it's only 2 liters between the Holton and Conn - really only a slight difference in bell volume - but here the bells are the same, so the 2 liters must come out of the branches. It's a bigger difference there in the branches, right?

Fundamentally, measuring an exponential-conical shaped bugle in terms of total volume, will weight the observation very strongly towards the large end. If tubas were invariably designed to the exact same exponential geometry all the way to the bell end, then it would be immaterial, but they clearly aren't - they particularly differ right where it will confound the measurement the most. Some tubas may have mostly conical bells with a small flare near the top, others are more exponential, etc. Manufacturers do this by mutual agreement, a policy begun long ago with the intention to discourage tuba players from filling their tubas with beer.

[jtm]

... Manufacturers do this by mutual agreement, a policy begun long ago with the intention to discourage tuba players from filling their tubas with beer.

This cuts to the heart of it.

[KingTuba1241X]

Don't understand your question and I don't know the 2 tubas in your picture.

That's true 6/4 Rudy and a 6/4 American style..

You can hardly see the difference.

Ah yes, try removing your rose colored glasses perhaps.

[pjv]

ahem

[donn]

A tuba being totally exponential would be a total different instrument. If you keep the same bell size the exponential horn will have much less volume. Keeping the volume the same would give you an enormous size bell.

I'm not sure what "totally exponential" means here, but I think if you measure a tuba in a couple different places, you will find that the bugle expands at an increasing rate - it isn't simply conical. Each place you measure, take two measurements some distance apart, and find the rate at which the tubing expands in that area - (Circ1 - Circ0)/Distance . In the bell, it may expand as much as 1:2, between bottom and top bows 1:4, branch before the top bow 1:6.

[Rick Denney]

Anything that would be exponential or radial or whatever would be in the bell section, and only the part that has a compound curve. Everything else will be roughly conical, though maybe with cusps where the rate of conicity changes.

Wide, shallow flares provide a different impedance match to the room than more minimal flares. But the main difference, it seems to me, will be propagation and directivity. That’s a hunch, but it matches my qualitative observations.

Rick “and it has a bigger effect than height in what the player hears” Denney

[bloke]

Talking to "numbers people" and referring to "my own experience, and with no numbers", that person and I are necessarily going to talk past each other.
I find - via experience - that playing either crazy-tall-belled tubas or bell-front tubas provides the same challenge: operator difficulty in hearing what is produced.
When I have a bell-front tuba (and am attempting to ascertain how it actually sounds to others - both loudness AND resonance characteristics), I'm able to rotate the bell around at a "stupid-looking" angle, and - suddenly - I can hear it much better...There's no such option available with a nearly 46"-tall kaiser.
With BOTH (if I have not been playing either of them for several weeks) I tend to overplay, but eventually realize/discover/remember that I've been playing (for the past _____ minutes) "as loud as $h!t", and then adjust my production for the lack of feedback I receive.
The first time a (very fine, very accomplished, and prestigiously-trained, very versatile, and mostly B-flat player) friend of mine played my kaiser (in a large/very-high-ceiling room in blokeplace), he also reported that he could not hear what he was doing.

The stubby, wide-belled, haven't-ever-seen-one-before-but-it-looks-a-whole-bunch-like-some-York-tubas currently-under-construction Holton BB-flat is much easier to hear, and - though super wide-belled (yet never actually - whether as manufactured, or due to abuse - "pancaking" - as do King bells) - sounds much more like "bloke" (perhaps: if a model/style of tuba much be chosen) - somewhat 186-ish...or 188-ish) than "a really wide-belled expected-to-sound-fluffy tuba".

Numbers - often - factor out wide-ranging operator differences, (well...?? yes...?? ) because - otherwise - numbers could not be produced.

Anything that would be exponential or radial or whatever would be in the bell section, and only the part that has a compound curve. Everything else will be roughly conical, though maybe with cusps where the rate of conicity changes.

Wide, shallow flares provide a different impedance match to the room than more minimal flares. But the main difference, it seems to me, will be propagation and directivity. That’s a hunch, but it matches my qualitative observations.

Rick “and it has a bigger effect than height in what the player hears” Denney

[donn]

Anything that would be exponential or radial or whatever would be in the bell section, and only the part that has a compound curve. Everything else will be roughly conical, though maybe with cusps where the rate of conicity changes.

Those numbers were from an existing tuba, a BBb Kalison 2000. Bell 1:2, branch opposite bell 1:4, branch next to bell 1:6. Where I understand conical to mean the rate of expansion is constant - same rate. I'm too lazy to measure further down the smaller branches, but intuitively you can see that as the tubing narrows, the rate of expansion decreases to imperceptible.

Measurements - across 27cm bell 44.5cm->58cm, across 27cm branch 25cm->31.5cm, across 16cm branch 16cm->19cm

I am quite likely not using "exponential" in a proper technical sense, and maybe that's where you two can't see this geometry in the tuba and I can - I just mean, the rate of expansion grows, as you move towards the bell end. Not that it grows according to any particular standard function.

[dp]

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pffft!

[bloke]

That was the most interesting and accurate thing posted so far in this thread…
…though I did really enjoy the colors in that fireworks minimalist drawing.

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pffft!

Do you want to contribute something interesting?

[Doc]

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pffft!

A good "PFFFT!" from Dale is LONG overdue.