Discussion of tuba sizing

[peterbas]

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.

[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.

[peterbas]

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?

If you have 2 tubas, a CC and a BB, with the same size bell piece (1 tennon) then the volume in bell is the same off course. Let the Bb be pure conical after that towards the tuning slide. The CC has 2 feet less to make the same change (bore also same for the two) in volume so it can not be conical all the way, it must have places where it changes quicker from shape. This is the art of cutting a tuba from BB to CC without messing up the intonation and other things.

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.

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.

[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

[peterbas]

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.

Still can't see it, must be blind.

[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.

[peterbas]

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

There is also the difference for higher frequencies (harmonics) because they are better in following a rapid flare bell than the lower frequencies so they will be more present in the sound then in a minimum flare bell.

[peterbas]

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.

Calculating the angle for the different parts and in total I get this.
begin + 250 cm = 0,5°
+ 75 cm = 1°
+100 cm = 2.8°
+25 cm = 30°
bell edge something like 50 - 60°
So yes the rate (angle) gets bigger toward the bell.

To get a feel of the power of three for volume.

The angle from begin to 25 cm from the bell edge = 1.1°
Total volume = 40 liters + 22.6 bell = 62.6 liters

The angle from begin to bell edge = 2.9°
So one straight conical tube from tuning slide to bell gives
Total volume = 272 liters
Now that's what you could call a fat tuba.

[peterbas]

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

The turning of the recording bell is a nice illustration of the directivity created by the bell. A lot more volume in the cone like space where the recording bell points too.

For a short tuba the bell is about 20 cm from your ears. A tall bell being about 20 cm higher, that is a doubling of the distance to 40 cm.
The doubling of distance means a lost of 6 dB in sound power.
In terms of an audio amplifier you need to turn it up from 25 Watts to 100 Watts.

This loss of power is again also frequency dependent. The higher the frequency the smaller the cone the sound travels in (think trumpet)
So the player hears less higher frequencies then the listener, but with the tuba playing up the effect will be less then for trombone or trumpet.

[dp]

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pffft!

[peterbas]

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pffft!

Do you want to contribute something interesting?

[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.

[Alex C]

I was once in a very intense discussion about the nomenclature of 6/4 vs 5/4 vs 4/4 when Ed Jones, suggested that if the manufacturer says a tuba is a 5/4... it's a 5/4. When they say it's a 6/4, it's a 6/4.

If they don't say, I don't suppose it matters.

[matt g]

I was once in a very intense discussion about the nomenclature of 6/4 vs 5/4 vs 4/4 when Ed Jones, suggested that if the manufacturer says a tuba is a 5/4... it's a 5/4. When they say it's a 6/4, it's a 6/4.

If they don't say, I don't suppose it matters.

There’s a nice subtlety here. Melton/Meinl-Weston, and Rudolf Meinl both make a fairly nice lineup that spans sizes over the same design ideal. Rudy tubas can be labeled whatever and are relevant to that brand. The 3/4, 4/4, 5/4, and 6/4 all size up respectively. Same with the once 2145, 2155, 2165 and now 3450, 3225, 5450, 6450. In other words, if the manufacturer is making a complete lineup, then the sizing makes sense in context of their product offerings.

[lost]

158 replies and growing. Clearly a topic of interest for those who dismiss the topic.

I agree manufacturer's have their own lines and can call them what they want. I think the OP was meant to apply some useful standard across product lines since this is what we do already. Example is the prevalence of tuba players calling vintage American monsters or mammoths 6/4 horns when they were according to the manufacturer lines one step above their regular size horns (5/4). This makes things murky because they wouldn't be comparing them to their product lines.

Also medium, standard, monster, mammoth are just better branding terms for 4/4 and 5/4. This has always historically been done by companies to distinguish size difference in tubas they sell. This is useful information to know for a buyer and not just clever marketing. There are many tuba players who don't like big horns.