Untuned student instruments

[Udi]

I'm teaching groups of two three young baritone players in a school and noticed a consistant peculiar tuning problem with instruments from a certain brand: The fundemental Bb is almost a semitone flat. In other words when you play a Bb scale it's rather in tune within itself, but low Bb is extremley low. Higher Bb is ok.
To me it seems very odd, and it also doesn't setlle with what I think I know about overtones.
I did meet untuned partials an octave apart before on some much better instruments, but never to this extreme. I don't get how that can happen, acoustic-wise.

Any thoughts?

[Alex C]

Make sure the students are not letting the embouchure "collapse" on the "low note."

I have encountered a number of brands which seem to spread the octave and the problem is not limited to student-level or "off-brand" tubas and euphoniums.

The mouthpiece can have an effect on tuning, as can the embouchure of the player but the stretched octave is inherent in some instruments; you will encounter it more than you'd like.

[KarlMarx]

Any thoughts?

Yes!

But in the spirit of this board we should let it to the professionals kicking horseshit into a fertile educative atmosphere.

[Udi]

Hey KarlMarx, I'd be happy to hear you'r thoughts and promise to respect what you have to say. If you really don't feel comfortable posting on the thread, write me a PM.

[Udi]

Do these horns do this when you or any other more developed player plays them?

I can play them much better, of course, but the problem persists.

Have you or anyone else tried a number of the more common beginner-type mouthpieces on these things?

Unfortunately, I don't have many MP's to choose from, they don't carry much more then what came with the instruments. But I do believe if I was convinced other MP's could make a change we could buy them. I teach as part of a music program initiated by a good conservatory. It aims to give kids and their parents a taste of music studies so in a year or two they'll come study at the conservatory.

Good luck and sorry to not any better ideas. You are not alone with this problem, however.

It's good to know I'm not alone. And don't be too sorry, I guess some of these students will continue their studies and get to play much better instruments.
I'm still curious about the physics of these phenomena, though.

[Rick Denney]

I'm still curious about the physics of these phenomena, though.

One thing I've learned in my reading is that an in-tune series of partials is by no means a given on a conical instrument. The taper design is critical, and changes in the taper can have effects all up and down the partials. That's not the same thing as the overtones of a low note, however.

Some scientists have even postulated that the pedal tone isn't really the fundamental of the instrument, but it sure seems that way to me on my smaller instruments where I can reach the pedal tones with more assurance.

Rick "who thinks nothing is a given" Denney

[Carroll]

I have found this phenomenon to be quite common, as well. The youngsters often push their embouchures forward (like a kiss pucker) for low notes... sometimes starting as high as the "D" in the staff. I can usually correct this habit by having them play siren sounds on the mouthpiece alone. This way they can change the range without changing the set up.

[corbasse]

I got a YBB 321 last year through my wind band, and the fundamental on it is very low and slightly instable. I'm using the mouthpiece that came with it, although I tried a Wick 2, Kellyberg and Bach 18 on it as well without any improvement.
I'm blaming the horn, since on the B&S clone I had before it I had no problem with the fundamental at all.

[Dean E]

I'm teaching groups of two three young baritone players in a school and noticed a consistant peculiar tuning problem with instruments from a certain brand: The fundemental Bb is almost a semitone flat. . . .

When a horn is flat with the tuning slide pushed in, there is a design problem. That is the case with my three Eb, 3-valve, vintage (about 1917-1930) horns. Some older horns were designed to play in low pitch, but that doesn't explain why A=440 is barely attainable with all slides pushed in, rather than with slides in the middle of their adjustment range.

I understand your puzzlement. It doesn't make sense to me that new school horns were copied (or "reverse engineered") from older, low-pitch models. Maybe school horns are designed to be used only with the slides pushed in an attempt to avoid denting.

[tubaguy9]

I know one instrument that absolutely, SUCKS at intonation is a Weirl brand Bass Bone. Our school has one of these, and the tuning B-flat is flat even with the tuning slide all the way in. Then, if this weren't odd enough, you play a B-flat below that, and it's sharp...I'm not sure of the petal note, really. So, if the euphs are Weirl brand, that's why...

[ken k]

We had two old Getzen baris at my elementary school when I started teaching there years ago that were just like that. These horns were pretty old, probably from the 50's, and were not in great condition. Eventually I had to stop using them, they were so bad I couldn't stand it any longer. They were a little better when I played them, but even I had to consciously keep that low Bb lipped up. Obviously a beginner is not going to be able to do that. and what note does an elementary baritone player play probably 70% of the time?.... more than any other note..... you guessed it.....

I dont know if a mouthpiece change would help or not. Perhaps a shallower mouthpiece like a 12C would help? If you can get one to try you can always buy cheap generic 12Cs, like Faxx or even kellys might work.

ken k

[Ryan_Beucke]

Depending on the age group, I would be it's more of an embochure problem. Many teachers tell their brass students to use a "high buzz" and a "low buzz" for different notes. What happens is when the students are playing a low Bb, they end up playing with way too loose an embochure and it comes out flat but technically still a Bb.

[Udi]

When a horn is flat with the tuning slide pushed in, there is a design problem ... Some older horns were designed to play in low pitch ... I understand your puzzlement. It doesn't make sense to me that new school horns were copied (or "reverse engineered") from older, low-pitch models.

I didn't mean the instruments were flat, just fundemental Bb in relation to other notes.

Udi, are you talking about oval baritones?

No, these arn't oval baritones, and they're not Jupiters either. The Jupiters we use don't give me too much problems.

Many teachers tell their brass students to use a "high buzz" and a "low buzz" for different notes. What happens is when the students are playing a low Bb, they end up playing with way too loose an embochure and it comes out flat but technically still a Bb.

I'm sure what you say is partly true about me. I sometimes have to ask them to play "loose" to get that Bb. Then again, students on those Jupiters don't show this problem, and I meet the same problem when I try to play these instruments.

[Donn]

peculiar tuning problem with instruments from a certain brand: The fundemental Bb is almost a semitone flat. In other words when you play a Bb scale it's rather in tune within itself, but low Bb is extremley low. Higher Bb is ok.

I have one like that! Alexander, 4 top piston valves. The way I remember it, that low Bb was not only low, it was somewhat flat in terms of resonance. A little like a `false pedal'.

The intonation problem appears abruptly at that Bb. Have tried different mouthpieces. I have been meaning to acquire a dentist's mirror and look through the valves, but have no reason to believe the answer is there. I have spent some time cleaning it - there was some odd waxy gunk in the valves. Slides come off with a reasonable pop.

I got it used. The previous owner was apparently a student, and if he or she had it for any length of time, and it was playing like this, it would have been enough to abort a musical education. It's really useless. There isn't any big intonation problem above that Bb, but it has quite a large bore to be used as a tenor horn.

Like you, I'm interested in the acoustical explanation. I guess there might be something in there that interferes with that particular standing wave so strongly that it's forced off pitch? And doesn't bother higher open notes because they have more nodes and can better afford to lose that one?

[Rick Denney]

Like you, I'm interested in the acoustical explanation. I guess there might be something in there that interferes with that particular standing wave so strongly that it's forced off pitch? And doesn't bother higher open notes because they have more nodes and can better afford to lose that one?

What it means is that the resonance peaks of the impedance curve when that note is played don't add up to the correct frequency. That could be caused by a range of issue, including some of the upper harmonics canceling each other, which might also explain the change in tone.

Pinpointing the cause as a result of the symptom requires clairvoyance, however, because of the range of influences on the impedance curve.

Impedance is just resistance to the flow of sound, and varies by frequency. When you buzz 58 Hz into a Bb tuba open bugle, the waves will reflect back from the open bell such that the return pulses arrive in time to reinforce the outgoing pulse. That's what makes the note easy to play. If some additional impedance is affecting that particular frequency or one of its overtones, the return pulse will be attenuated so that it won't reinforce the buzz. If it's out of tune, a buzz of a slightly different frequency will be reinforced. If the buzz isn't reinforced anywhere, there will be no good-sounding note there and that's what I usually call "stuffy". It can be caused because the important harmonics are filtered by the presence of spurious frequencies in the buzz--this is why beginners sound bad--or because the buzz is being forced on a non-resonant frequency. Both of those symptoms can exist separately or together.

Being able to describe the physics doesn't provide much help with the solution, except that a tuning stick will help a tuba that buzzes on the wrong frequency but won't help a tuba that doesn't resonate well on any nearby frequency. That problem could be caused by a faulty taper design (or a good design made fault by dents in the wrong places), poor mouthpiece selection or fit, or even a dead mouse in an inner bow.

Having a bad note doesn't mean notes in the same harmonic series will be affected. A taper design that doesn't resonate at 58 Hz may well resonate at 116 Hz and higher harmonics. There is nothing given, especially with conical instruments.

Rick "studying a lot of AC lately in preparation for ham radio exams" Denney

[Chuck(G)]

If you're wondering about the flatness of the 2nd partial (low Bb on a BBb) tuba, a lot can be explained by the bell effect, I think.

A narrow bell will tend to flatten the lower partials more than the upper (this has little to do with the size of the bell flare, but rather the taper of the bell itself). A wide bell + bottom bow taper will tend to make the lower partials sharper.

I think the stinky 3rd partial on many 6/4 blunderblusses is less of a matter of the 3rd being flat and more of the 2nd being sharp (think about it). As you go up the series, the bell effect matters less, but at the bottom it can make substantial difference.

For mid-range problems, the bell will have little or no effect on intonation.

This is my experience, at any rate.

On some very old big European tubas, the taper is so wide that the intonation is almost unusable. Simply rolling up a piece of cardboard into a more-or-less cone shape and shoving it down the bell can do wonders.

[MaryAnn]

I've seen this on 3-valve piston Eb tubas and on cheaper, front-bell Eb alto horns. The "octave" is rather securely a 9th, and basically impossible to lip into tune. Since I don't personally have this problem (the octave being a 9th) on any of my better instruments, I've always labeled it a construction design problem and not purchased said instruments. So it's not the kids' fault, this time.

MA

[Chuck(G)]

...and old gigantic Martin BBb tubas don't have this problem at all because ___________ ...

While they look big, I don't think they're as large as, say a 20J throught he bottom-bow-bell branch. They're wound a lot tighter and are more squat, so they look bigger, but start at the end of the bell and measure the diameter at intervals going toward the mouthiece. I think you'll find they're smaller.

Just a guess, Joe.

[Donn]

If you're wondering about the flatness of the 2nd partial (low Bb on a BBb) tuba, a lot can be explained by the bell effect, I think.

Well, for my Alex baritone, it isn't exactly the 2nd partial, it's only the 2nd partial Bb. And maybe A, but G and below is fine.

Anyway, more compelling evidence that it isn't the bell: I fixed it!

I really have made some attempts to clean this thing out, but this evening just on a whim, I ran magnet balls all the way through it. I could hear something fall out of the bell end afterwards, like large grit, probably nothing that could have made any difference, but at any rate, now the Bb comes up "A#" on the tuner, when before that procedure it was more like A.

Now I just need to get the valves moving a little more freely, and figure out how to deal with the absurd ergonomics.

[Chuck(G)]

Now I just need to get the valves moving a little more freely, and figure out how to deal with the absurd ergonomics.

I suspect that you might have closed up a leak somewhere.

I'm not saying that the bell's the only thing--just that it can be a contributing factor in bad low-range intonation.

Consider what the bell (actually the conical section after the valves) does acoustically over a simple striaght pipe. It raises the pitch of the lower harmonics more than the upper harmonics. A strongly flaring bell will tend to move the lowest harmonics up more than a bell that flares less strongly. If the bell effect is too strong, then the space between the 2nd and 3rd partials will be too narrow. Tuning one's instrument so that the 2nd partial is in tune results in the 3rd partial sounding flat.

See, for example:

http://www.phys.unsw.edu.au/jw/brassaco ... html#bells

Right now, I've got a big old Bohemian horn in the shop for work. I'm guessing that the 20" bell may not be original (I'm not sure, but the way it's attached makes me wonder). The notes toward the top of the staff are almost unplayably flat. I suspect that a smaller bell might correct that.

I'm doing a lot of guessing here, but the horn's going to be pulled apart for overhaul anyway, so I'll have a chance to check my theory out.