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

[tubashaman2]

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[Dean E]

. . . . Now, models like the Firebird, Kodiak F, and the JBF classic have a free blowing low range. . . .

Good question. I'm new to F tuba, and I played for about ten minutes on one of the above models at the Army Tuba Euphonium Conference last week and never could get a C (second line below the staff) to sound at all. I kept looking for an obvious mechanical problem, such as an open water key, to no avail.

[tubashaman2]

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[Rick Denney]

For those who want to discuss how to play the low C, start with this thread: viewtopic.php?f=2&t=29486&p=257650

There are other threads that may turn up in some searches where we have pondered what caused the low C "problem". We have agreed that it's a real problem. We have also agreed that it's not necessarily unique to F tubas. For example, I have to work about as hard on the low F of my Holton as I do on the low C on my F tubas. Some F tubas (as well as contrabass tubas) have a rock-solid second-partial fourth valve.

Steve mentions that his B&S makes the low C easy after it suffered a dent in a certain spot, and he has actually provided a photograph. That would suggest to me that the spot is a node or antinode. On the pedal, the antinode is at the bell, and the only node is at the embouchure. On the second partial, an octave up, the node is at the chops and at the bell, and the antinode is halfway along the bugle. When the fourth valve is in use, the bugle is 16 feet long, just like a C tuba. Considering the bell effect, that dent will be somewhere on the outer branch over on the left. Now, let's look at the picture:

viewtopic.php?f=2&t=28732" target="_blank

It may not be exactly at the right spot, but it's a deepish dent and it might well cause a minor reflection at the antinode. A minor reflection from the antinode would reinforce the resonance on that note, just as the major reflection from the bell does.

What might be different about other tubas? Well, let's think about that. My 621 does not have the low F issue at all. What's going on with that tuba about 7 feet in (counting the bell effect) from the bell rim? The instrument is about three feet tall, and it has a narrow bottom bow. The spot in question might be at the top bow on that instrument, perhaps even where the top bow begins. Maybe that curve leading into the top bow is providing the necessary reflection to reinforce that pitch. The tall rotary F's will put that antinode on the straight outer branch section, I would think.

Or, maybe not. I'm not about to conduct any experiments.

My suspicion is that second partials with lots of straight valve tubing are already a bit sketchy on tubas, and the shape of rotary F's reinforces that. All rotary F's have a leadpipe, the machine, the tuning slide, a dogleg (maybe), an upper bow, a bottom bow, and a bell. Your average contrabass has at least two more main bows, and puts the 4th-valve second partial antinode much deeper into the instrument.

Rick "just guessing" Denney

[Sam Gnagey]

I've always held the opinion that the older F tubas needed two more "U" curved branches in the bugle section. To test this I reconfigured my original Meinl F that way by hybridizing in branches and a different bell from a little old Eb. The pitch on the resulting horn was lousey, but the low range opened right up. (The Meinl F was pretty well trashed, and I ended up using all the rotors on my CC projects as 5th valves.) If you study the Yamaha Bobo F and the YFB-621 you'll see that they incorporate this concept in the design of those horns which all have great low Cs. The very compact little Meinl F(maybe 182?) also has those extra branches and a pretty good low range.

[Matt G]

I agree (with Sam) that it would seem to be a design issue. The majority of German F tubas are of very similar shape, and display similar problems. However, I also think it has to to with the rate of taper.

The old B&S bass tubas that many love with the smaller bore, the Yamaha F's (822,621), and the Gronitz all seem to have a taper rate that seems to be consistent through most of the horn. On the other hand, horns like the PT-15 seem to have a very quick initial taper to the valves, a fairly long (in proportion) valve section and subsequent nearly-cylindrical section, a decent taper through the body, and then an oversized bell throat. This inconsistency seems to effect the playing characteristics.

When I look at the new and improved MW CC tubas, I can't help but notice small details that seem to address rate of taper issues from the previous models. As evidenced by current reviews, this has seemed to fix the 5450 (nee 2155) issues, in terms of overall response and intonation. It seems to me that often the low C issues in F tubas comes from a intonation deficiency in the horn in that register. Normally, even when one gets the right embouchure going they find that there are some oddities to the intonation scheme in that register.

[MaryAnn]

Given the difference in slotting between my Lawson horn bell and my Schmid horn bell, I think there is credence to the tapers theory. (The Lawson bell decreases the inherent squirrelliness of the horn's high range by a noticible amount, for both the player and the listener.)

I also think there is credence to the node-anitnode theory. What I'm wondering is, since we have the picture of the magic dent that instantly fixed the low range, if it wouldn't be easy to take a very small magnet and manage to get it inside the tubing at the proper location for the anti-node (seven feet from the bell rim, if I understand Rick correctly) and see if that same magic effect can be brought about.

MA

[tubashaman2]

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[Wyvern]

My personal observation would be that maybe it could be a result of the long bell section to the bottom bow as that is a design feature my Haag Eb has in common with most German style F tubas and the Haag has the same low register characteristics. I also noted the same trying a Cerveny Eb designed in similar style.

I have got used to coaxing the Haag in that register and find my new PT-15 similarly responds, so personally do not find it a big issue.

[Rick Denney]

What I'm wondering is, since we have the picture of the magic dent that instantly fixed the low range, if it wouldn't be easy to take a very small magnet and manage to get it inside the tubing at the proper location for the anti-node (seven feet from the bell rim, if I understand Rick correctly) and see if that same magic effect can be brought about.

(I suspect metallic resonance makes a much bigger difference on a horn than on a tuba. Partly it's structural--the shape of the horn bell is much less rigidly supported. And partly it's because the characteristic horn sound, especially when played loudly, includes some metallic sibilance, as with trumpet.)

The (slightly modified from your suggestion) notion of rolling a small dent ball inside the tuba and holding it in place with a magnet is hilarious (and brilliant--if it works). I have to try it. Finally, a guilt-free application for that magnetic dent removal system that I bought.

Rick "reports to follow" Denney

[Lee Stofer]

One aspect to consider is this; The smaller the bore size, the greater the sensitivity of an instrument. I had really not thought about it that much until I was speaking to Chip Owen of the Fox Company, asking him about how to better go about de-denting bassoon bocals. He told me that he does not recommend repairing bassoon bocals unless absolutely necessary. Unlike a tuba leadpipe that is over .500" bore to sometimes over .900" bore, the bore of a bassoon bocal is quite small. Mr. Owen told me that he could take a new fox bocal, ever so slightly bend it, and then bend it back into original shape, and even if it was not visible to the eye, a seasoned player could tell the difference by playing it.

So, since F tubas are generally our smallest, shortest tubas, it would stand to reason that the sensitivity would be greater on an F tuba than what one would experience playing a CC or BBb instrument. Even Eb tubas generally seem to be more forgiving. To some degree, I think that these tendencies are present in most if not all tubas, but the larger instruments are just more forgiving than their smaller, fussier siblings.

I'm not sure that the number of branches necessarily makes the difference, because Cerveny and B & S have both made some exquiste jewels in F, but the F tubas with the most notable low range do seem to be more of an Anglo-Saxon design. Conn-Selmer had a prototype F tuba at the ITEC in 2002, and I was hoping to see more of this project. The instrument was short and stout, and had pretty good intonation. The tone seemed a little, "buzzy" to me, but something that could be fixed. I'm planning to build a custom F tuba this year, and I hope to crack the code on what makes a great, OK, or not-so-good F tuba.

One thing I have noticed is that the C's on an F tuba, like the G's on a C tuba, are greatly affected by the plumbing. On tubas with a short leadpipe, mostly seen on piston-valve instruments, there is an important node in the main tuning slide area. If an instrument has a long leadpipe and a lot of rotor valves, that node is more likely to be in the valve cluster somewhere, which would undoubtedly have an affect on response. And, a curved tube acoustically behaves like a straight tube of larger diameter, so having that node in the main tuning slide, and having subsequent nodes in curved tubing instead of a straight tube might make the difference. I do know that the Cerveny CFB 654-6 I used to own had a short leadpipe, reversed tubing on the small side of the main tuning slide, a very large crook for the main tuning slide, and more curves than straight tubing in the instrument. The resulting instrument was a pleasure to play, something that I don't say about all F tubas!

[Doug Elliott]

On the pedal, the antinode is at the bell, and the only node is at the embouchure. On the second partial, an octave up, the node is at the chops and at the bell, and the antinode is halfway along the bugle.

Am I not correct that all brass instruments act as closed-end tubes, and resonate only odd-numbered harmonics, and therefore always have a node at the embouchure and an antinode at the bell end? Therefore there is another node and another antinode on the second partial, wich is acoustically a third harmonic.

That's what I always thought... maybe I'm wrong.

[Donn]

Am I not correct that all brass instruments act as closed-end tubes, and resonate only odd-numbered harmonics

I would say you are not correct, on that point. Only the clarinet family, of the wind instruments I know about.

The 3rd partial might arguably be the tuba's most useful. On a Bb tuba, that would be F down to B, right below the bass clef.

I thought about the C question while blowing my old 3 valve Eb giant bass this morning, and occurred to me to ask those of you whose F tubas fail to delight on low C, is the `false' Bb below it stronger? Just curious.

Are there ANY universal tendencies in horns that cannot be compensated for by changing my unwillingness to practice more?

Are we talking about universal tendencies? I have an Eb tuba that I can't play in tune to save my life, at around C in the staff and a couple notes either way. Want to buy it?

[imperialbari]

It is interesting to read about the assumed influence of variances between tall instruments with fewer bows and more compact instruments with more bows.

The Meinl travelling F tuba probably has too many other parameters changed for a valid comparison. Still experiences from playing that instrument may be relevant, as may experiences with the new Tornister Tuba in its F variant:

http://www.hornboerse.de/lshop,showdeta ... rni,,,.htm

Without thinking along the paths of this current thread, I wrote this recent posting about two different modifications of the traditional British 3+1P compensating Eb tuba into F tubas:

viewtopic.php?p=277716#p277716

Applying the ideas of fewer bows being the reason for problems, then the Boosey sample temporarily owned by Neptune should have displayed problems beyond those of ergonomics. That is not what I read in that thread.

Lee Stofer’s observations about nodes placed within rotary valve clusters are very interesting as is his observations about the reversing of the first branch of tuning slides. I am aware about the problems of creating stable structures (stays would be impossible), but in my opinion all slides should be “reversed”. The second best thing would be to chamfer/undercut all male branches directed against the airpath.

I doubt the F being the smallest of the tubas is the reason for problems. I see sort of a continuum from Eb flugelhorn through BBb tubas. It is true, that the flugelhorns in Eb and Bb traditionally have had tuning problems, partially due to the tuning being in the leadpipe. But the euphonium appears to be a quite efficient member of the family of conical brasses, and it has a minimum of bows.

Klaus

[Wyvern]

Applying the ideas of fewer bows being the reason for problems, then the Boosey sample temporarily owned by Neptune should have displayed problems those of ergonomics. That is not what I read in that thread.

That Boosey F played just like a British compensated Eb, but pitched a tone higher.

[Rick Denney]

On the pedal, the antinode is at the bell, and the only node is at the embouchure. On the second partial, an octave up, the node is at the chops and at the bell, and the antinode is halfway along the bugle.

Am I not correct that all brass instruments act as closed-end tubes, and resonate only odd-numbered harmonics, and therefore always have a node at the embouchure and an antinode at the bell end? Therefore there is another node and another antinode on the second partial, wich is acoustically a third harmonic.

That's what I always thought... maybe I'm wrong.

When the note is resonating on the second partial, it is an octave above the fundamental. The pedal F at 43 Hz has a wavelength of 26 feet (it's 34.4 feet for a pedal C at 33 Hz), on the fundamental. Nodes are at whole wavelengths away from the lips. The bell opening is half way between those (a little short of halfway, actually, because of the bell effect). That would put a node at the lips and an antinode at the bell opening--when the pressure is high at the lips, it's low at the bell and vice versa. But an octave up at the low open note of the tuning scale, the wavelength is necessarily half that. The wavelength of an F at the bottom of the staff is 13 feet. The bugle is a little less than that. We are forcing a node at the bell because that's the pitch we are buzzing, but if the horn could not resonate it, we'd have no usable tone.

At every point in between those nodes, the pressure pulse will lag behind the buzz pulse an increasing amount, until it finally lags behind far enough to be in phase again, and that's at the next node. Thus, there are no nodes in between those, at least at that frequency (but keep reading).

The point at which the pressure wave opposes the buzz is the antinode and that will be about half way between the nodes.

The wavelength of the low (not pedal) C is 17.2 feet. When we push down the fourth valve on an F tuba, we get a bugle that is a little shorter than that. Thus, the antinode will be about the middle of that wavelength, or about 8.5 feet from the chops (or from the effect bell end, which is maybe as much as a bell diameter beyond the bell opening).

I don't think I agree with Lee that there is a nodal effect in the valve body anywhere on that frequency. The B&S F tubas have a short leadpipe by rotary standards, because it goes straight into the lower port of the 5th valve instead of wrapping over the top of the upper bow and coming into the valves from above as is the case with most rotary tubas.

More to the point, to reinforce a resonance, one needs a reflected pulse that is in phase with the pulse being produced by the buzz.

But here's where it gets silly: There are many overtones in tuba sound. Each one of those overtones is representing sound waves of shorter wavelength than the pitch being buzzed. Each one has nodes and antinodes at a range of point along the bugle. It may be that the dent in question reinforces the resonance of one of those overtones enough to make the buzzed pitch lock in more solidly. That's why I throw up a big question mark. The testing require to know (by acoustic analysis) is formidable. But Lee's impression of whether there is an important node or antinode closer to the mouthpiece than I've suggested maybe based on an important overtone. As I've measured, Overtones 4-6 are very strong in tuba sound.

Rather than trying to fit a model based on the assumption of a closed or open tube, I just calculate the wavelength directly. The wavelength is just the speed of sound divided by the frequency. That tells the story of where the nodes and antinodes are with certainty, at least for that frequency.

Rick "knowing that those overtones resonate more or less as a result of the taper design" Denney

[imperialbari]

Applying the ideas of fewer bows being the reason for problems, then the Boosey sample temporarily owned by Neptune should have displayed problems those of ergonomics. That is not what I read in that thread.

That Boosey F played just like a British compensated Eb, but pitched a tone higher.

My, smaller, Boosey F-tuba also plays the British tuba way. It doesn’t have the very big sound like my Besson 981 in Eb, but then the bell only is 337mm wide versus the 480mm of the 981. Its sound is a nice in-between of my Yamaha 641 euphonium and the 981. And that was the reason why I bought that old Boosey, when I saw the chance to do so.

It has been hard to settle on a mouthpiece for my Boosey F, which has been equipped with a large receiver by a former owner. It sounds fantastic with a PT-50, but finer controls in low dynamics upper range are impossible. The same to some degree goes for the MF 3-H, which i use on the 981. The DW 4L and 5L are too restricting, so I look forward to receiving the next model to be tested, the blokepiece.

On a different tangent of this thread:



Søren made me aware of a smallish Miraphone F tuba for sale in Sweden. I didn’t like its dents, as I always think in the costs beyond the sticker price, when considering instruments. Yet its horizontal tuning slide implies an extra loop. Does anybody on TubeNet have experiences with this more compact rotary F design?

Klaus

[imperialbari]

That looks like an early 180 design to me. But who knows? Does anyone here have scans from Mirafone catalogs from that long ago? I have never seen that logo nor such a pronounced keel on any Mirafone tuba! also, there is almost no nickel silver on the thing. I am guessing early 1950s. Great photo!

The photo is from the Swedish sales site (somewhat similar to the US Craig’s lists). That page no longer is available, so the tuba must have been sold. I contacted the seller, who sent me these additional photos, which I will upload along with the one from above, as the link may go dead at some point of time.

Miraphone started out shortly after WWII based on pre-war know-how and with limited tools. This is not meant derogatively, as it was impressive that they started up at all under the given circumstances. They may very well have continued making instruments the old style for the European market. The valve transmission and the water key both look being old style like the keel. But then it is not much more than 25 years ago the British tubas started coming without the ball-buster.

The US market, at a wider scale like all levels of schools, may have discovered the German tubas after 1960, but as I see it that American market also influenced the German instruments. If by no other means then by creating the basis for expansion and modernising of facilities and methods.

Klaus

[The Big Ben]

That looks like an early 180 design to me. But who knows? Does anyone here have scans from Mirafone catalogs from that long ago? I have never seen that logo nor such a pronounced keel on any Mirafone tuba! also, there is almost no nickel silver on the thing. I am guessing early 1950s. Great photo!

I just bought a detachable bell 186 BBb, by the numbers built in 1964, that has a keel just like that. It's a little something to get used to after a horn with a smooth bow guard.

BTW: Dan O. just tuned it up with rebuilt rotors, a new mouthpipe and some work on the waterkey/tuning slide tubes and it plays very, very nice. Looks better, too, with quite a bit of cleaning, buffing and some dent work on the stack to facilitate the mouthpipe installation. Dan filled and rebent the mouthpipe to make it look "just so" and also taught his apprentice Paul a bunch of tricks for rotor work in the process. Everything is extra cool for me! Thanks, Dan and Paul!

Jeff "Learning to use the fourth valve" Benedict

[sloan]

For those who want to discuss how to play the low C, start with this thread: viewtopic.php?f=2&t=29486&p=257650

There are other threads that may turn up in some searches where we have pondered what caused the low C "problem". We have agreed that it's a real problem. We have also agreed that it's not necessarily unique to F tubas. For example, I have to work about as hard on the low F of my Holton as I do on the low C on my F tubas.

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?