What in F tuba design makesthe low range stuffy (or not)

[The Big Ben]

I've been watching this thread since it started. I hate to sound like a big jerk, but here goes . . .

I think the single biggest reason that the low range on any instrument (not just F tuba, but it seems to be the main target due to tessitura) is stuffy is the player attached to the mouthpiece. Sorry, but I've got to call it as I see it. If a given instrument doesn't function the way you want, don't play that one, if you have a choice. If you don't have a choice, practice until you are in control . . . not the horn.

I will now dismount the soapbox . . . I apologize in advance if I've offended anyone. Of course, YMMV.

You're not wrong and there is plenty on TubeNet to support you. Bloke wrote a prescription for folks with 'F Low Range Disease".

It's apples and oranges to the OPs topic. The OP asked: "We know some F tubas have better low ranges than others. Why is that?" Had some good input, including Sam, a maker of tubas who has practical experience and others who have a great technical knowledge of physics and design.

I've found it fascinating.

[awaters]

I always enjoy this thread in part because i don't understand science and am glad that there are tubists who do!
I had a B+S orchestral F and i switched from CC to F every note(a real pain... suggested by teacher but it worked) to get the low C on the F tuba to speak. I now play the Willson F which works fine on the C and notes down below.

[Rick Denney]

You have to "work" to get a low F on a BBb tuba?

Obviously either an inferior horn, or an inferior player.

Is the tuba for sale?

Only if you want it to sound good.

But, yes, on a Holton, the low F requires a special blow. It's not just push the buttons and blow. You have to feed the resonance, and if you force it, it will not sound. It's easier played 1-3 with a pull, but the potential sound isn't as big. The fourth valve has a larger bore, much like the fourth valve on B&S-style F tubas.

Rick "wondering why that would make the instrument unacceptable" Denney

[Rick Denney]

Many have complained about my description of nodes and antinodes, etc.

But here's what I know, and at the end what I suspect:

1. Nodes occur at the lips, and in whole wavelengths downstream from that point.

2. Antinodes are halfway between nodes, approximately (the approximate part is because of the taper).

3. The wavelength is what it is to produce the note in question. So, if an instrument playes a fundamental 26-Hz pedal Bb, the next node will be 43ish feet away from the mouthpiece. If that isn't the case, it won't be a 26-Hz Bb.

4. If an instrument plays a 58-Hz second-partial Bb, then the next node will be 21ish feet from the mouthpiece, which is a bit outside the bell. Obviously, the node is at (or near) the bell when playing the second partial, and the antinode is at (or near) the bell when playing the fundamental. I see no alternative from a physical point of view.

5. So, for calculating the fundamental, we must consider the instrument as closed on the mouthpiece end and open on the bell end.

6. But obviously that "rule" doesn't work for playing the second partial, otherwise the second partial would not resonate and be playable.

7. I don't know this, but my suspicion is that much of the arm-waving that goes on about how a tube is characterized is based on what others have written in the context of playing fundamentals.

8. I do know this: When calculating the wavelength and therefore the nodes and antinodes in free air, one must know the frequencies (including those of the overtones), the speed of sound, and make an assumption of air density (which is affected by altitude, atmospheric pressure, and temperature).

Rick "that is what I know, and what I suspect" Denney

[imperialbari]

If those O-rings are intuitive, they may be worth their price.

K

[Allen]

... ...
1. Nodes occur at the lips, and in whole wavelengths downstream from that point.

2. Antinodes are halfway between nodes, approximately (the approximate part is because of the taper).

3. The wavelength is what it is to produce the note in question. So, if an instrument playes a fundamental 26-Hz pedal Bb, the next node will be 43ish feet away from the mouthpiece. If that isn't the case, it won't be a 26-Hz Bb.

4. If an instrument plays a 58-Hz second-partial Bb, then the next node will be 21ish feet from the mouthpiece, which is a bit outside the bell. Obviously, the node is at (or near) the bell when playing the second partial, and the antinode is at (or near) the bell when playing the fundamental. I see no alternative from a physical point of view.
... ...

Rick, I think you slipped on one fundamental point: The nodes are a half-wavelength apart, not a whole wavelength.

This is why a cylindrical organ pipe (open at both ends) can have a length of 16 feet (a half wavelength) for the C at 32 Hz. There is an antinode at each end. If we stop one end of the pipe, it is now a quarter-wave resonator, and that 16 foot long pipe will sound the C at 16 Hz (assuming the pipe builder has got things voiced well for that lower pitch).

Tubas are more complicated, as we know. A BBb tuba with an open bugle length of about 18 feet has no resonance at all at the pedal Bb (29 Hz). We can play that pitch because of all of the tuba's other resonances that coincide with harmonics of that note. The real bottom resonant frequency is about 39 Hz (Eb), known as the false tone. This bottom resonance is broad and poorly reinforced, as few of the other resonances of the instrument coincide with harmonics of that note.

The first good resonance of a tuba is what we call the second partial (in the case of a BBb tuba, 58 Hz, or Bb). I know there is a node at the mouthpiece, and an antinode somewhere in the vicinity of the bell. How many other nodes and antinodes there are in-between (I guess one each), and exactly where they are is something we all would like to know, for this note and all of the other notes too. This would be a great research topic. After it's published, we will know where to aim our hammers!

Cheers,
Allen

[MikeMason]

Sometimes i long for the good ole days.If we observed a phenomenon we couldn't explain,we just chalked it up to "magic" and got on with our lives(which were only around 35 years because we didn't believe in germs)

[sloan]

Sometimes i long for the good ole days.If we observed a phenomenon we couldn't explain,we just chalked it up to "magic" and got on with our lives(which were only around 35 years because we didn't believe in germs)

So...if the low C is weak on you F, the solution is to bleed it?

[tubatom91]

Sometimes i long for the good ole days.If we observed a phenomenon we couldn't explain,we just chalked it up to "magic" and got on with our lives(which were only around 35 years because we didn't believe in germs)

So...if the low C is weak on you F, the solution is to bleed it?

Leeches... just stick 'em on and let her rip. perhaps you could add them to the mouthpiece for extra mass or somthing

[sloan]

Sometimes i long for the good ole days.If we observed a phenomenon we couldn't explain,we just chalked it up to "magic" and got on with our lives(which were only around 35 years because we didn't believe in germs)

So...if the low C is weak on you F, the solution is to bleed it?

Leeches... just stick 'em on and let her rip. perhaps you could add them to the mouthpiece for extra mass or somthing

Do you attach the leeches at the nodes, or the anti-nodes?

[ztuba]

You guys are awesome!

[jtuba]

My young self could not for the life of my figure out how to play the low C on any rotary F tuba I played. Now I have two rotor Fs that I don't have a problem with, a new school and old school intrument that rock down there. The first time I played a Miraphone 180 I put it down right away, the next time I played a 180 at Dillon music two years ago, I didn't want to put it down. Sure some instruments work better than others, but I've learned not to be so heavy handed as I was as a younger player. As a result, I'm less inclined to think it's a design issue, and I'm all for using hardware to solve software issues

[MikeMason]

i think this thread(and all threads for that matter) needs a picture of some buxom smiley german cuties drinking big steins of beer... now THATS magic....

[Rick Denney]

Rick, I think you slipped on one fundamental point: The nodes are a half-wavelength apart, not a whole wavelength.

Dang it! You are right. I also got (rightly) beat up in a PM.

The problem is (as I suspected) the definition of nodes and antinodes. It's not a node at the mouthpiece end, but an antinode.

The node is where the pressure stands (in the standing wave) at zero, which follows the pulse by a quarter wave. There are two nodes in each wavelength, where the pressure crosses through zero, at 1/4 and 3/4 waves behind the pulse.

The more I think about it, the more I realize you have to add up all those harmonics to determine where the nulls are for any given note.

That second-partial fourth-valve C on an F tuba has a null at the bell, the mouthpiece, and halfway through the instrument all at the same time. The bugle is one wavelength long on that partial. Therefore, pressure oscillates at points 1/4 and 3/4 of the way along the bugle. The bugle is about 17 feet long on that note, so we are talking about pressure oscillation points about 4.3 feet in from the bell and from the mouthpiece.

But it will be greatly affected by the harmonic energy. The 4th, 5th, and 6th overtones are stronger than the fundamental, by my own measurements, and they will each have their nodes and pressure points at their respective frequencies and distances long the bugle. Those points will range at 1.2 to 1.7-foot intervals, which quickly overlap and interact. The arithmetic becomes pretty intractable in a hurry, especially considering the effects of the tapered bugle, which are significant, at relocating those nodes.

So, I conclude that the only reasonable means of finding those pressure points, where a dent might have an effect, is by experimentation. I think that Mr. Tucci, when commenting on Steve's dent, was either acting on the experience gained from such experiments, or he was being polite.

But I'm still going to roll a ball in the the tuba and hold it in place with a magnet to see if I can duplicate the effect.

Rick "stopping just short of building a monster spreadsheet" Denney

[MaryAnn]

Oh Rick, just go build the spreadsheet. You know you want to!!!

Waiting with a hat-full of stuffy Cs for that dent-ball experiment.

MA

[sloan]

That second-partial fourth-valve C on an F tuba has a null at the bell, the mouthpiece, and halfway through the instrument all at the same time.

No, it doesn't. Please go and look at the diagrams in the link I posted.

Don't make me send another PM. I might have to start using imaginary numbers...

No matter what convention you chose, the bell end is the opposite of the mouthpiece end. Brasses are open at one end and closed at the other. Open ends behave differently than closed ends.

Oh, and when you build the spreadsheet...the taper is only part of the story - you might find the effects due to the flared bell and the mouthpiece wreak havoc with the theory you've put forth so far.

One more time...my understanding (see the links I posted, above) is that the effective length of the bugle contains 1/4, 3/4, 5/4, 7/4, ... complete waves (see the diagrams). This gives you a harmonic series with a, 3a, 5a, 7a,... The flared bell changes the effective length of the bugle as a function of wavelength - this affects one end of the spectrum; the mouthpiece affects the OTHER end of the spectrum. Combined, these two effects compress the series of resonances to (close enough for musical work) create a sequence x, 2f, 3f, 4f, 5f,... (where 'x' has no simple relationship to f, or a). If you buzz 'x', you get no help from higher harmonics (which won't resonate) so it will sound and feel "different". If you buzz 'f' (along with it's harmonics), the tuba will emit only 2f, 3f, 4f,... - which will work out OK because your ear and brain will fill in the phantom 'f'. [Doug Elliot claims that conical instruments resonate at 'f' - I would *really* want to see confirmation on that, but note that ears don't count].

That's the basic story for a a straight bugle with minimal taper (say...a herald trumpet). Add taper (worse - add tapers that CHANGE at various points in the bugle), and wrap it, and you get lots and lots of local modifications. I haven't found any really good descriptions of these complications [and would dearly love to be pointed at same so that I can become less ignorant].

And, yes...the arithmetic becomes intractable - but IF IT HAD SUFFICIENT MONETARY REWARD these computations are not beyond the current state of computing. With enough funding, I think it would be fun to convert 3D scans of arbitrary tubas into simulated waveforms. The problem is, there are a limited number of funding agencies who might be interested in this - and most of them probably already have something very close to this up and running in their design labs (probably not scans of arbitrary horns - but certainly design tools that get it mostly right without creating actual dents in brass).

[Matt G]

And, yes...the arithmetic becomes intractable - but IF IT HAD SUFFICIENT MONETARY REWARD these computations are not beyond the current state of computing. With enough funding, I think it would be fun to convert 3D scans of arbitrary tubas into simulated waveforms. The problem is, there are a limited number of funding agencies who might be interested in this - and most of them probably already have something very close to this up and running in their design labs (probably not scans of arbitrary horns - but certainly design tools that get it mostly right without creating actual dents in brass).

In all reality, just some application of analytical geometry (at an albeit high level) should reveal a good bit. The problem is this stuff doesn't come free and would seem a bit like witchcraft in the instrument industry. The Holton Harvey Phillips horns were supposedly computer designed, and they aren't highly regarded.

There are plenty of agencies doing significant study in waveform analysis, signal analysis and propagation. Unfortunately, it has no relevance to tubas!

Oddly enough, a good number of these folks have some understanding of music. However, they probably feel that there is no need to really push the application of rigorous study into that field, since current methods seem to be good enough, even if they are subject to high degrees of variation.

[bill]

My M-W182 has a 2-3 5th valve. I thought that maybe using 2-5 fingering instead of 4 would change the feeling of the C (not stuffy, btw, just different from Bb). It did but not much. Now I am wondering . . .

[Donn]

Not that I lack faith in the scientific approach, but it seems to me that we could improve our fundamental grasp of the problem by making better use of the collective Tubenet pool of experience.

Everyone knows that some F tubas offer a less than satisfactory experience on low C and other notes in the low register, but as far as I know, our design theorists lack information like

• an inventory of common F tubas vs. their low C response
• a shared vocabulary, in the sense that we all mean the same thing when we talk about the problem - sometimes it sounds like these tubas refuse to make a sound, and then later we're just talking about a different feeling of resistance. Useful reports on F tuba models need to be more specific - how bad, which notes, etc.
• are there other observable deficiencies in this model - intonation, tone quality? (Well, the claim has been put forth that tone quality may suffer in tubas with a good low C.)
• broader information on tubas in other keys - Eb basses should probably be included in the inventory.

Not real data, since there's no way to filter out variation in playing ability, and there could even be spurious trends there, if people who are better prepared to make a tuba work are also more likely to favor certain models. But collect the data, sort out the good vs. the bad in a reasonably comprehensive way, and who knows, the answer might be as plain as the nose on your face. And anyway, the scientists back at the lab might be interested to know exactly what problem they're trying to solve, too.

[MaryAnn]

I've been watching this thread since it started. I hate to sound like a big jerk, but here goes . . .

I think the single biggest reason that the low range on any instrument (not just F tuba, but it seems to be the main target due to tessitura) is stuffy is the player attached to the mouthpiece. Sorry, but I've got to call it as I see it. If a given instrument doesn't function the way you want, don't play that one, if you have a choice. If you don't have a choice, practice until you are in control . . . not the horn.

I will now dismount the soapbox . . . I apologize in advance if I've offended anyone. Of course, YMMV.

Ah, well, you see, you sort of missed the point of the original post and the ensuing discussion. It's not about how to play the low C; it's about "why the low C is the way it is." People with a technical bent simply like to talk about this kind of thing. Like guys who collect trains; you don't tell them that they should quit playing with their Lionels and go take a real train to get where they're going, because that's not what it's about. It's about playing with them; technical people like to play with technical ideas.

Over the years I've mentally categorized musicians into two types: there are the math-music types (of which I am one) and there are the art-music types. The former love the technical aspects separately from the musical aspects, and the latter's eyes roll back in their heads when the technical types get going, and start spouting things about "just play the music already!" The twain don't understand each other.

MA