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You can hardly see the difference.KingTuba1241X wrote: ↑Wed Jan 20, 2021 7:09 pmThat's true 6/4 Rudy and a 6/4 American style..Don't understand your question and I don't know the 2 tubas in your picture.
Ah yes, try removing your rose colored glasses perhaps.peterbas wrote: ↑Thu Jan 21, 2021 11:06 amYou can hardly see the difference.KingTuba1241X wrote: ↑Wed Jan 20, 2021 7:09 pmThat's true 6/4 Rudy and a 6/4 American style..Don't understand your question and I don't know the 2 tubas in your picture.
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.donn wrote: ↑Thu Jan 21, 2021 10:55 amYes, 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?
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.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.
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.
) because - otherwise - numbers could not be produced.
Rick Denney wrote: ↑Thu Jan 21, 2021 3:42 pm 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
Still can't see it, must be blind.KingTuba1241X wrote: ↑Thu Jan 21, 2021 11:13 amAh yes, try removing your rose colored glasses perhaps.
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.Rick Denney wrote: ↑Thu Jan 21, 2021 3:42 pm 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.
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.Rick Denney wrote: ↑Thu Jan 21, 2021 3:42 pm 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
Calculating the angle for the different parts and in total I get this.donn wrote: ↑Thu Jan 21, 2021 5:26 pmThose 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.Rick Denney wrote: ↑Thu Jan 21, 2021 3:42 pm 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.
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.
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.bloke wrote: ↑Thu Jan 21, 2021 4:08 pm 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...??
Rick Denney wrote: ↑Thu Jan 21, 2021 3:42 pm 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’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.
