Intonation Relating to the Taper of the Main Bugle

[MackBrass]

This topic is very interesting.

I'm no scientist, but if an even taper is critical to intonation, how could any of those "BBb cut to CC" horns ever hope to play in tune? I've got to imagine the taper is all shot to hell in those cases....

This is very interesting, the older alex 163 CC tubas were basically cut down from the BBb 163 model. Most of the CC's had some real intonation issues but kept the great sound and core. Even when using alternate fingerings the core on the alex CC was great. There have been two older from the 60's alex CC tubas, one I owned and one I almost bought that I have played where no alternate fingerings were needed.

On the modern alex CC tubas the intonation is consistently very good but to get there the whole tuba was redesigned to fix the issues. Are they perfect? No but they are much better and still have the great alex sound of the older model.

There have been several non alex cut BBb to CC tubas that I have played where the intonation was workable but the core of the sound was different from one note to another. Also, some of the cut tubas I have played had some notes that centered well but others that did not. The HB21 is also a cut BBb rotor to a piston CC tuba, this CC version does have some centering issues compared to the HB2 CC but plays well in tune.

One major factor is assembly within a specific model where no two of the same play the same and have noticeable differences. I have owned miraphone 186 models from the 60's, and 70's as well as the jinbao 410 copy. The worst of the bunch was the tuba i owned made in the 60's but the sound was great. The best for intonation was the jinbao where I find no slide pulling is needed. Now this may be an attribute of having developed my ears and playing to play in tune opposed to letting the horn play me as it did when i was less experienced.

All in all, if you focus on one area on design where the intonation is perfect, you may screw up another area where intonation, sound, and focus could become an issue. Best bet on any design is get it as close as possible where the compromise is at a minimum. The older alex CC is a great example where intonation was compromised for a great sound not duplicated by any other model. The PT 6 and the Wiseman 900 is about as good as it gets for intonation but still not perfect as the top line g on every one i have played rides a touch high but I don't have to pull a single slide while playing them.

The last consideration in developing a new model is the player testing them for approval. What works for one person may not work for another as everyone is different. Someone may play a specific model and the main slide is all the way in while someone else can play the same exact tuba and they might need to add more length to the main slide to get it in tune, both of which can have an impact on the whole harmonic series.

Will there ever be a plug and play tuba? I dont think so as even the most expensive ones have their issues.

[imperialbari]

There are many factors determining intonation of any given instrument. Taper rates, taper to cylindrical ratios, and so on.

If all or most of these factors add up to the same pitch tendencies, then slots are narrow. If they point in different directions, then slots are wide.

To me the worst scenario is about narrow slots placed at the wrong pitches.

On the other hand with wide slots: a certain design of narrow bore baritones with wide bell throats made by Dutch, French, and Czech makers I always felt myself hopelessly out of tune, even if the notes maybe would have satisfied a tuner. There was no way to make the overtones line up to a reasonable pitch.

Klaus

[pjv]

Which leads me to wonder;
would a tuba built in a very warm area be too long for proper usage in a very cold area?

I've noticed that the difference in slide lengths at extreme temperatures can be about an inch (either way).

[iiipopes]

Or more. I played an outdoor concert once with a souzy bell facing directly into the sun. I started out with about 3/4 inch pull. The sun heated up the souzy so much by the end of the concert I had the main tuning slide out as far as I could without dropping it, and was still lipping down.

Conversely, last Saturday, I played outdoors, shoved in, and was still flat for the first piece until both the outdoor ambient temperature and the horn finally warmed up enough to pitch.

Many modern tubas offer both a 443 and a 440 slide; all you have to do if you're going to playing in a lot of cold weather is to order the 443 horn, which will flatten to 440 or even lower in the cold, and have the extra longer 440 slide to use when going back indoors. Many older tubas can be fitted with an appropriate longer or shorter main tuning slide to account for temperature variations. This was common when there were both HP and LP horns; many old HP tubas have main tuning slides with an extra curl added to bring the pitch down. The issue, of course, is making the outer slides short enough that when cold the slide can pushed in to bring the horn up to pitch, while still being long enough that the legs of the inner slide can pull the pitch back down as necessary as the temperature increases.

And if the temperature difference is really down, say, at 40 degrees Fahrenheit or so for the concert, as opposed to 68 to 75 degrees indoors, and stays there, it might be prudent just to get the horn "warmed up" to where it will be played, pull the main slide out 3/4 inch, check the relative decrease in pitch with an electronic tuner, and just tune the entire band down so you can still have leeway in the slide as the temperature changes during the concert.

[pjv]

I like the double-tuning slide idea. I just finished a theater tour and every grand piano was tuned differently (441, 442.5, 443, blah blah). And it's not just the main slide that has to be adjusted at different tunings or temperatures, but all the tuning slides.

I guess if a tuba designer wants to get it right, they at least have to build a tuba that can still play at 443 in a mildly cold room.

[pjv]

No.
What I meant is that a tuba must also be comfortably playable at around 443 since this is about as high as we tune nowadays.
The "in a cold room" has nothing to do with the piano but it does to the tuba, which can require the tuning slide to be moved in a good half an inch to an inch in a cold environment.

[iiipopes]

Wide slots. That is the answer. So notes can be lipped as necessary. Most of us do it subconsciously, anyway.

[Rick Denney]

Short version: Q.

Long version: Wait for Mr. Denney's thorough,yet concise and clear, explanation, which should be following momentarily.

DG

Hmmm. I'll give this two minutes. Q is the quality of resonance. The sharper the peak in the amplitude with respect to frequency, the higher the Q. It's a term from designing resonant electrical circuits using resistors (to lower Q), capacitors, and inductors.

If you want to experiment with a lower Q, open your water key. Pitches are much more flexible, but the system is no longer as able to filter out noise components in the sound. So, purity of sound (at one frequency, at least) and Q are related.

But because tubas are resonant on a range of frequencies (the fundamental and a collection of overtones), the interaction of these overtones might change the perceived pitch and width of the slot. A good good signal might resonate a more accurate range of harmonic overtones, and give a full pitch and clear tone, even in a system with lower Q. A poor signal might excite only a few overtones and fail to filter out all the noise elements, leaving a fuzzy, wide tone. Better players (with better signals) prefer instruments that give them the great mix of harmonics but with more flexible pitch (flexible being defines as not undermining those harmonics or adding noise when the pitch is changed). Less good players may need that high Q, and depend more on instruments to manage pitch for them.

Rick "two minutes is up" Denney

[windshieldbug]

That has ZERO to do with octaves being in tune. You are talking about "Just Intonation", in stretch tuning of a piano, the 4ths & 5ths and octaves are 'stretched' out of tune (sharp) when the keys are struck so they then settle into tune (equal temperament) as they decay.

Yes, perfectly in tune with a tuner (equal temperament) doesn't sound awful, but doesn't sound as good as just intonation. But NONE of that matters if the OCTAVES are not in tune. Any ensemble (or pipe organ) with low voices that are flatter than the voices above just sounds muddy and dull as the harmonics don't properly align.

+10