Joined: 24 Dec 2018 Posts: 3303 Location: Endwell NY USA
Posted: Sat Apr 25, 2020 11:12 am Post subject:
And a corollary aspect is that in order to get the same amount (quantity, not speed) of air flowing through a smaller aperture requires a greater difference in the pressure levels.
For trumpet playing that means that when a smaller aperture is used, it's necessary to 'blow harder' (to increase the pressure in the mouth) in order to have the same AMOUNT of air flowing. And the amount of air flowing has a direct influence on the loudness. Because loudness is directly related to the amount and distance of lip movement (that movement being the 'energy source' needed to get the air column inside the trpt vibrating).
That is part of the reason for needing more air pressure when playing loud high notes - the aperture is smaller, and the loudness would decrease if the air pressure was not increased.
Jay _________________ Most Important Note ? - the next one !
KNOW (see) what the next note is BEFORE you have to play it.
PLAY the next note 'on time' and 'in rhythm'.
Oh ya, watch the conductor - they set what is 'on time'.
Joined: 26 Jun 2017 Posts: 1545 Location: Virginia USA
Posted: Sat Apr 25, 2020 11:13 am Post subject:
Interesting Darryl. The begging question is that whether in trumpet playing the low side pressure remains constant. We know the high side varies. The increased aperture size will lead to a more rapid evening of the pressures in the two chambers or depletion of the high pressure side (or breath). _________________ Bb: Schilke X3L AS SP, Yamaha YTR-6335S
C: Schilke CXL, Kanstul 1510-2
Picc: Kanstul 920
Bb Bugle: Kanstul
Bb Pocket: Manchester Brass
Flugel: Taylor Standard
Bass Trumpet: BAC Custom
Natural Tr: Custom Haas replica by Nikolai Mänttäri Morales
First of all. The video subject is pure velocity through a SINGLE variable which is the varying aperture size with constant pressure difference.
The popular myth is that aperture size alone influences velocity with all other things equal. Which it doesn't.
Jay wrote:
Quote:
And the amount of air flowing has a direct influence on the loudness. Because loudness is directly related to the amount and distance of lip movement (that movement being the 'energy source' needed to get the air column inside the trpt vibrating).
Wrong Jay. Loudness is influenced by air power applied to tone. Not lip displacement. The "Energy" source is the air pressure x air volume of the air "pulses". Not the wiggling lips. The lips simply determine the frequency of the pulses, they provide no energy (or power) to the sound.
The air power provided is the air energy / time, that is: air pressure x air volume / time
or
power provided = air pressure x air flow
the sound power out of the instrument is then:
air power in x efficiency
Power is increased by increasing the air pressure supplied by the player. The player uses air pressure to control loudness of tone. Air flow does then follow depending on the total air flow resistance at that instant.
cgaiii wrote:
Quote:
The begging question is that whether in trumpet playing the low side pressure remains constant. We know the high side varies. The increased aperture size will lead to a more rapid evening of the pressures in the two chambers or depletion of the high pressure side (or breath).
In the case of playing a tone; the supply pressure, that is, the air in the oral space, is much more constant and calm relative to the air pressure in the mp cup. Which is varying rapidly and drastically.
...The popular myth is that aperture size alone influences velocity with all other things equal. Which it doesn't....
Being a long-time student of the instrument, I'm sincerely trying to understand this. In regards to the quoted statement, what is it we are witnessing when we put our thumb over a water hose (supposing the water pressure is constant)? Isn't the water moving faster when we diminish the size of the opening (aperture)?
In the case of a "water aperture" the principle still applies. If the pressure on each side of the nozzle is constant, then velocity of flow through that opening would be independent of its size.
The case of a garden hose is unrelated to trumpet playing. But in that case a very long and narrow water supply hose will have significant viscous losses of pressure for high flows. Introducing a nozzle will limit the flow and the pressure bearing on the nozzle will then increase to be nearer to the supply pressure. This geometry does not exist when playing the instrument because the resistive instrument and aperture are always in existence when playing any tone, and the airway is significantly lower in resistance. Air is also less viscous than water by far.
Joined: 24 Dec 2018 Posts: 3303 Location: Endwell NY USA
Posted: Sat Apr 25, 2020 3:00 pm Post subject:
kalijah wrote:
Wrong Jay. Loudness is influenced by air power applied to tone. Not lip displacement. The "Energy" source is the air pressure x air volume of the air "pulses". Not the wiggling lips. The lips simply determine the frequency of the pulses, they provide no energy (or power) to the sound.
...
---------------------------
Yes, sorry about my mistake. The lip movement acts as a pulsating valve to release the air. The amount (area) of lip area opening and closing probably affects the quantity of air flow per pulse.
Regarding the garden hose example. When there is not a nozzle on the end of the hose, the water pressure inside the hose is drastically reduced. If there is a water pressure gauge near your water meter or main shut-off valve, you can see a drop in pressure when a toilet is flushed.
Placing your thumb (or a nozzle) on the hose causes an increase in the internal water pressure inside the hose (because the out-flow is restricted), and that increases the amount of 'pressure difference' that your video explains.
Jay _________________ Most Important Note ? - the next one !
KNOW (see) what the next note is BEFORE you have to play it.
PLAY the next note 'on time' and 'in rhythm'.
Oh ya, watch the conductor - they set what is 'on time'.
Joined: 13 Nov 2001 Posts: 9830 Location: Chicago, Illinois
Posted: Sat Apr 25, 2020 3:12 pm Post subject:
Why is it that if I blow at a constant level of power with my tongue arched up and forward (causing the air to make a sissing sound as it comes out), I can feel that the air velocity is clearly faster and hitting the palm of my hand in a much thinner stream (and it turns a wind vane faster) than if I blow with the same level of strength but have my tongue down flat in my mouth? Same supplied air pressure; same atmospheric pressure. And yet...
And why is it that putting a nozzle on my garden hose makes the water shoot out the end far faster (in a thin stream), even though the supplied water pressure is the same and the atmospheric pressure is the same?
A nozzle is a spout on the end of a hose or pipe used to control the movement of a fluid like water or air. A convergent nozzle is a nozzle that starts big and gets smaller-a decrease in cross-sectional area. As a fluid enters the smaller cross-section, it has to speed up due to the conservation of mass. To maintain a constant amount of fluid moving through the restricted portion of the nozzle, the fluid must move faster.
The arching tongue acts as a nozzle.
I appreciate the time you took making that video and uploading it Darryl.
The tongue cannot act as a nozzle if the air pressure at the boundary of the tone-playing aperture is already at lung pressure. Any attempt to do so will introduce significant resistance into the flow path between the lungs and aperture. The air pressure available to the playing aperture will then be reduced below what is provided by the lungs. Due to the resistive viscous and turbulent flow over a "hissing " tongue.
Joined: 24 Dec 2018 Posts: 3303 Location: Endwell NY USA
Posted: Sun Apr 26, 2020 7:07 am Post subject:
John Mohan wrote:
Why is it that if I blow at a constant level of power with my tongue arched up and forward (causing the air to make a sissing sound as it comes out), I can feel that the air velocity is clearly faster and hitting the palm of my hand in a much thinner stream (and it turns a wind vane faster) than if I blow with the same level of strength but have my tongue down flat in my mouth? Same supplied air pressure; same atmospheric pressure. ...
----------
My guess is that the effort to have your 'tongue arched up and forward' is also changing the shape of your lip aperture. And that change in lip aperture is focusing your air stream into a smaller cross-sectional area. That more focused stream of air would feel like it had more speed, and would be more effective in turning a wind vane.
Maybe try the experiment blowing thru a drinking straw (or shank of a mpc) so the aperture really is held constant?
And that is assuming your 'supplied air pressure' really is the constant.
I find it difficult to maintain the same internal feeling of air pressure when blowing and moving my tongue position.
When thinking about fluid flows and their amount of pressure and energy, it's critical to also consider the 'flow rate' and the cross-sectional area that the directed 'flow' is exerted upon.
For example in a water nozzle, the constricted flow (and the energy of the moving water) is exerted onto a smaller area.
Jay _________________ Most Important Note ? - the next one !
KNOW (see) what the next note is BEFORE you have to play it.
PLAY the next note 'on time' and 'in rhythm'.
Oh ya, watch the conductor - they set what is 'on time'.
In the case of a "water aperture" the principle still applies. If the pressure on each side of the nozzle is constant, then velocity of flow through that opening would be independent of its size.
The case of a garden hose is unrelated to trumpet playing. But in that case a very long and narrow water supply hose will have significant viscous losses of pressure for high flows. Introducing a nozzle will limit the flow and the pressure bearing on the nozzle will then increase to be nearer to the supply pressure. This geometry does not exist when playing the instrument because the resistive instrument and aperture are always in existence when playing any tone, and the airway is significantly lower in resistance. Air is also less viscous than water by far.
With all due respect, Darryl, I find a contradiction between your first and third sentences.
kalijah wrote:
In the case of a "water aperture" the principle still applies....
The case of a garden hose is unrelated to trumpet playing....
If the principle still applies, then the two would have a relationship. Can you please explain the obvious contradiction and how you apply your understanding of physics when playing, say, high notes (i.e. DHC) vs. low notes (below low C)...at relatively the same volume. IOW, what changes for you, and how do you teach your students to play higher, especially.
My point was that the behavior of a garden hose nozzle depends on the complete system. However, the nozzle velocity does depend on the pressure differential across it, regardless of the system. But even in the garden nozzle, there comes a point where the nozzle width becomes much LESS than the length of flow in the nozzle, The flow, and the velocity of flow out of the nozzle will then diminish due to the viscosity of the water.
IF you connect the hose nozzle to a low-resistance/ constant pressure source the velocity will be independent of the nozzle size.
My point in the video is that the prevailing belief is that a progressively small nozzle has increasing flow velocity in ANY and ALL cases. Which is false.
Again, one must consider the complete system, the nozzle does not increase the supply pressure in a garden hose scenario.
My video does not specifically address a garden nozzle OR a playing aperture. I will get to that in due time.
Joined: 11 Nov 2001 Posts: 3404 Location: Garland, Texas
Posted: Sun Apr 26, 2020 9:23 am Post subject:
This is a great introduction, Darryl. I think that a series of videos which gradually tackle the deeper physics issues, will really help everyone to understand your perspective. I know that it is helping me.
Interesting that folks are quickly jumping to the water hose analogy. All in good time.
Joined: 24 Dec 2018 Posts: 3303 Location: Endwell NY USA
Posted: Sun Apr 26, 2020 4:53 pm Post subject:
Hello Darryl, yep - I watched the entire video. Actually understood most of it (I'm not up on viscous effects).
Regarding the water hose situation, I think the key points start at 12:00, and then especially at 13:45.
The key item at 13:45 is that when there is non-trivial flow thru the long hose, the 'supply pressure' at the exit drops below the 'supply pressure' at the tank end of the hose. If the aperture is completely closed (or is very tiny so the flow rate is extremely low) the pressure at both ends of the hose would be nearly identical.
With a typical garden hose, the 'static pressure' at the closed nozzle cannot be maintained (it drops) as the nozzle is opened.
For trpt playing, the concern is how to generate and maintain high supply side air pressure (and the necessary flow rate) when we play loud notes - and especially with loud high notes.
Jay _________________ Most Important Note ? - the next one !
KNOW (see) what the next note is BEFORE you have to play it.
PLAY the next note 'on time' and 'in rhythm'.
Oh ya, watch the conductor - they set what is 'on time'.
Joined: 07 Jan 2020 Posts: 220 Location: Texas Gulf Coast
Posted: Sun Apr 26, 2020 5:34 pm Post subject:
Nice video. I immediately recognized the diagram as an AGA-3 orifice meter,
This was my life in the 1980's. My company sold monitoring equipemnt (SCADA), and I had to put the AGA-3 gas flow calculation in the remote unit software.
I think one source of confusion is a household water hose. Make the nozzle smaller, and the water goes much farther due to greater velocity. What's the difference with that and a person's lungs? The difference is what is supplying the water hose nozzle. The faucet delivers 50 PSI for small flow rates only. Wide open the faucet maxes out at 3-4 gallons per minute, and at a pressure near zero. So by making the nozzle smaller, that huge pressure drop is avoided.
I believe with a trumpet, the lungs can supply nearly constant pressure from piano to forte.
With a typical garden hose, the 'static pressure' at the closed nozzle cannot be maintained (it drops) as the nozzle is opened.
Well, how much it reduces. depends in the hose diameter and length and the flow.
It not just "static" pressure but total pressure. When the nozzle is closed and there is zero flow the pressure is indeed fully static. But it is still dominantly static for most nozzle-restricted flows,
But that is for another day. The confusion of understanding of static vs dynamic pressure is common.
Quote:
For trpt playing, the concern is how to generate and maintain high supply side air pressure (and the necessary flow rate) when we play loud notes - and especially with loud high notes.
Flow is rarely a problem for trumpet players. Pressure required can be improved by improving efficiency. Requiring less pressure, in general, to play. Equipment comes into play as well. "Large-bore" and "free-blowing" are NOT the answer to efficiency.
Staying fit is also an advantage to building increased pressure AND flow capacity. I get far more pressure strength benefits from fitness activities than sitting around doing breathing exercises. One must train the whole machine.
By the way Jay; "flow" is, by definition, a rate. "Flow rate" is a redundancy.
I believe with a trumpet, the lungs can supply nearly constant pressure from piano to forte.
I make that point often. The playing lip aperture resistance AND the instrument tone resistance are MUCH greater than the airway resistance. Even for low and soft notes. Such that the lung air pressure exists at all boundaries inside that pressurized space, INCLUDING where the aperture is located.
However the pressure is required to change for dynamics.
You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum
