2ba4t wrote:Thank you all for your kind assistance. Please correct me if the following is not right.
As I now understand it, the question of amplitude and energy within a sound wave, the amount of extra breath and how these are linked to volume and pitch is of great relevance to tuba players.
Amplitude, I learn, is the amount of ‘energy’ within the sound wave. The more energy, the louder is the sound at that pitch. Pluck a string very gently, with little energy, it will sound softly. Pluck with great force and it sound that note but loudly. You have put in more energy and that has become transferred to the results of that action – the production of a note by plucking - by making it louder. Bow harder on a violin or hit a drum more violently and the same principle applies. Blow harder on a tuba and again, more energy is produced and transferred to the sound wave.
It is called amplitude because the ‘amplus’ simply means large and we are measuring how ‘large’ the wave is. Amplitude tells us the amount of space between the highest and lowest points of the ‘wave’ commonly drawn to depict sound moving through the air. In fact, that very drawing is only a representation of the energy within that wave at a particular moment. The upper curve is when the molecules are crushed together by the sound energy wave (a node) and the lower is when they are free of any such pressure (an antinode). The space/distance between the highest and lowest part of the a sound wave on a diagram is its, you guessed, amplitude.
I now know that, obviously, if we blow ‘harder’, we blow with greater ‘energy’. Our abdominal muscles squeeze very powerfully inwards and this compresses the air within our body cavity beneath the lungs. The lungs are ‘violently’ pushed up and squeezed and the air in them ‘violently’ pushed out. This ‘violence’ is the energy we have put in.
If you play a crescendo, the greater energy put in by applying more force from the abs makes the air move faster. So the real ‘speed’ of the air moving is a vital factor and that speed does increase. The pitch should not change however because this energy is passing through your lips which you are still holding to the same tension. You are doing this by pressing them together and not changing that pressure despite the greater ‘push’. Despite the extra force/speed/energy - they therefore buzz at the same pitch. Sometimes, if you ‘overblow’ – push too hard – the lips are forced out of shape and you get a distorted sound.
Now comes the area which confused me. The ‘energy’ increasing amplitude is absolutely different from and not theoretically connected to the ‘energy’ you apply in squeezing your lips together to play a higher pitch – frequency. One application of force/energy is the pressing together of your lips. The second one is the pushing of air out of your lungs. These overlap however, because when you so crush your lips ever tighter together their rigidly means that only a greater force will succeed in making them vibrate. So you indeed need to blow harder – apply more energy – to make them vibrate at that higher pitch.
So our breathe is doing two entirely different things. One - it must be sufficient to make a buzz and the higher the pitch, the tighter the lips and the more air needed to make those lips vibrate against one another. Two – it is controlling the amount of energy going into the sound wave. When we blow harder there is more energy (which happens also to be making the lips buzz as required) and that is transferred into the sound wave. This extra energy increases its amplitude – volume.
Because the higher notes involve the lips squeezing more tightly and holding back air, less air escapes and less is used even when blowing high loudly. The lowest notes use huge amounts of air only too quickly because the loosely flapping lips necessary for the low pitch let it escape into the tuba.
Thank you.
I think you may be getting into the weeds a little too much, in terms of trying to understand what specifically is going on inside the body when playing. The issue with that is that we have relatively little conscious control over the muscles. However, we do have a great deal of control over the sound if we focus on the produce, i.e., the sound.
All you really need to be aware of is that when we play louder, we blow the air faster. When we play a higher pitch, the opening at the lips is smaller, reducing the amount of air flow. When we play lower, the opening is larger, increasing the air flow. Therefore, when we play at a very loud dynamic in the extreme low register, as we do in the large contrabass passages such as Wagner Ring Operas or the low parts in Bruckner Symphonies, we will empty our lungs in a matter of seconds, while pianissimo passages in the upper register may be sustained for a fairly long time.
Another important aspect for the tuba is that the air pressure inside the mouth is the lowest of all the brass instruments. You mentioned a few things that a troublesome: 1) squeezing your lips together to play a higher pitch, 2) pushing of air out of your lungs, 3) when you so crush your lips ever tighter together their rigidly means that only a greater force will succeed in making them vibrate, and 4) So you indeed need to blow harder.
1) We need to think of higher and lower notes as faster and slower vibrations. The faster vibrations are associated with a smaller aperture (lip opening) so that the lateral opening is shorter, just like when the string of a violin is shortened to play a higher note. The process is one of development over time so that the lip musculature can develop over time in order to be able to vibrate faster.
2) You never want to think in terms of pushing the air out of the lungs. Think of wind as air in motion outside the body. To develop this, think of blowing the air from the lips, as if you were trying to blow out a candle from across the room. A very good teaching aid for this is a child's pinwheel. If you try to push the air out of the lungs, the muscles of the torso will likely contract isometrically, which will severely inhibit the amount of air you can blow out.
3) Similar to 1) we don't crush the lips together. However, what you describe can be an accurate situation. The lips have tremendous ability to resist the blowing of the air, so much so that they can completely cut off the air, no matter how hard you blow. This is to be avoided at all costs in order to produce a good sound on the tuba. Arnold Jacobs discussed developing an embouchure that wants to vibrate. This is one reason he had his students buzz on the mouthpiece and on just a rim. It is harder to get the lips to vibrate on the mouthpiece alone than it is on the tuba, and it is harder to get them to vibrate on the rim than on the mouthpiece. If we can play on the rim easily, then we can transfer that ease of vibration back to the tuba and producing the sound becomes much more efficient.
4) So blowing harder works against this efficiency and ease in playing. Jacobs used the analogy of a string player playing loudly. They will move the bow quickly across the strings, but they will not press the bow into the string hard. If they did, they would get a very harsh, strident sound. The air is our bow, so we want to blow is fast past the lips, but we do not want to blow the air hard against the lips, or our sound will become very brittle and harsh. And, as Jacobs discovered through conducting studies with a decibel meter, when the air was blown hard against the lips (as measured by increased air pressure inside the mouth), the decibel level was actually reduced. When his students blew the air fast with little resistance at the lips, the decibel level increased.
But, the most important thing to keep in mind is that we must conceive of the sound we want at varying dynamics, and focus on that. Imitate in practice what a great tuba sound is starting at a mid dynamic in the middle register, and as you develop excellence there, expand it outwards, both in terms of register and dynamic.
Hope this helps.
