Does a larger tuba really produce a 'bigger' sound?

[JayW]

Well when it copmes to overall "SOUND SIZE" I would have to say that most BAT's produce this more easily than a smaller horn. However I do feel there is something to be said for Focus of Sound and its relation to projection. I have heard tubists perform on what is considered 4/4 size instruments but project just as well as any 6/4. There is however something to be said about the organ like quality a BAT can produce. I am sure there are far more experienced people who can "weigh" in on this issue far better than I.

[Tabor]

Here is a perspective from the classical voice side of the world.

I think the CC really produces a ‘bigger’ sound, or a ‘deeper’ sound due to stronger high harmonics, rather than low ones.

In voice, chambers which resonate and muffle (equalize and amplify) sound are called formants. We have two in singing, the throat and the mouth. The first is called a fixed and the latter is a variable formant (variable, because the mouth moves). The tuba is a fixed formant, because it doesn't change shape as it plays, therefore it "sings" only one vowel. That vowel can be changed, but the timbre of the tuba itself stays relatively constant (especially when compared to a singer).

In voice, one of the things people study is the vowel cone. One of the most open vowels (or bright vowels) is the aaa as in "hot" or "father" In the international phonetic alphabet, it is [a]. One of the more closed vowels (or dark vowels) is oooo as in "boot" or "lute" In the international phonetic alphabet, it is . In voice pedagogy, we learn that the vowels we hear are the way they are because of the particular overtones which are enhanced or muffled because of this second formant. A wider opening makes an [a] sound while a narrower opening makes an sound. This is easily demonstrated on a trombone with a plunger mute. It can make a "wa wa wa wa" (or [ua ua ua ua] in the international phonetic alphabet) sound which is more similar to the voice because the plunger mute makes the formant variable rather than fixed.

In singing, there is also something called the "singer's formant" which is probably the vibration of a tiny laryngal collar which resonates at the frequency of tape hiss regardless of the note being sung. This has to do with projection of the human voice and doesn't really apply to the tuba. This is not to be confused with the first or second formants.

From voice pedagogy and computer gizmos, we have learned that the bright vowels resonate higher frequencies with a greater energy ratio and carry better than the dark vowels, which resonate lower overtone frequencies with a higher ratio. This is directly applicable to the tuba. A big, wide bell resonates HIGHER overtones more strongly, than a smaller, narrower bell, which is shaped more closely to the vowel than the [a] vowel. The big fat tubas have that broad, encompassing sound because they resonate higher overtones better.

I would guess that the light fixture was the long tube type and was resonating the actual note you were playing, or a lower overtone because your Eb produced a tone which was right in tune with the length of the fixture, while the CC wasn't resonating exactly the same frequency. I am sure the harmonics were all present, but perhaps they were not resonated equally throughout the sonic spectrum by the two instruments. The other possibility, is that the pitch wasn't exactly the same.

[Tom]

If I have understood correctly, my PT-6 has more of an "American sound" although it is a German rotary tuba!

VMI/B&S/Meinl Weston seems to produce a lot of tubas geared toward the American market (ie, PT6, PT20, PT606, MW 2145, 2155, 2000, 2165, 2265, etc.) By the same token, they build lots of tubas that never make it to America...

The European market seems to be pretty different...made up mostly of rotor F tubas and big rotor BBbs. I had a great time trying tubas (in Germany especially) while on tour with the wind ensemble I play in last April-May...there were lots of models available to try that are considered "rare" or "obscure" in the United States, and there wasn't a CC tuba to be found, save one 4/4 Rudy Meinl.

[Rick Denney]

I think the CC really produces a ‘bigger’ sound, or a ‘deeper’ sound due to stronger high harmonics, rather than low ones.

My measurements certainly support your thesis. A range of well-spaced harmonics will create a difference tone at the fundamental, and will also give the sound color and texture. The notion of "rich in fundamental" is not something we'd really want, because the sound would be very weak even at high power.

But there's more to the issue of big and small tubas than harmonic content. There is also quantity of sound and propagation.

I have to say that I don't really think the BAT Yorkophones necessarily project better than smaller tubas. I do think they fill a big room with more vibration going in more directions. This is a propagation issue as much as a magnitude issue--volume rather than intensity. The testing I did can't see this, becaue it only sees what one microphone hears, and I was in a small room. In a big room, I think the listener hears a lot more harmonic content, with a lot more mixing of that harmonic content, because the sound seems to propagate in more directions at once and thus comes to the listener from more directions. Thus, the big instruments produce the sort of sound that attracts adjectives such as "blossomy" and "big" and "present", as opposed to "intense" and "loud". I suspect the same difference, on a smaller scale, would exist between a largish CC like a PT-6 and a largish Eb tuba.

Think of it this way: The instrument contains a volume of air. Playing the instrument sets that volume to vibrating. That vibrating air has two characteristics: Quantity and intensity. That is, how many molecules are vibrating versus how much they move during each vibration. All those vibrating molecules of air carry the pulses of vibration one to the other, and if you have more air vibrating to start with, it will vibrate more air outside the tuba. But the intensity of the vibration might be less. Thus, given the same buzz and equally efficient instruments, I think the large tuba will create more vibrating air at a lower intensity and the small tuba will create less vibrating air at a higher intensity. The latter may actually be louder, but the former will sound bigger in a room big enough to let that greater volume propagate. The total energy, or power, in the sound will be the same.

(There is a huge importance to that statement, "equally efficient", and that statement I think defines the differences between great tubas and less-great tubas.)

For those who have studied electricity, there is an analogue. Power (i.e., watts) is the product of the amount of electricity (current, measured in amps) and the intensity of the electricity (electromotive force, measured in volts). The same level of power can be represented by a high current and a low voltage as by a low current and a high voltage. For example, my generator produces 5000 watts. I can convert that to 12 volts, and produce 420 amps, or I can convert it to 240 volts, and produce only 21 amps, assuming my conversions are 100% efficient. Both, however, will do the same amount of work. The big tuba produces a higher current and a lower intensity given the same input power.

As to why the flourescent tube vibrated, it only means that the Besson produced a particular harmonic that resonated with the light fixture with more intensity than that frequency produced by the PT-6. I can't think of any useful conclusion that could be drawn from that. It certainly doesn't mean that the overall sound of the Besson was more intense than the overall sound of the PT-6.

Rick "who would measure the effect if he could think of how" Denney