kalijah

Rowuk, you are confusing air "speed" and air "flow" these are not exactly the same, but yet, are related if you are considering a fixed cross-sectional AREA of flow.

But anyway, may I comment on your original post?

Be aware that there is a huge diffence between a loudspeaker and the player/trumpet.

1. There is not net "flow" of air with a speaker. In playing there are "pulses" of air which have a net flow over time.

2. A loudspeaker has a somewhat resonant chamber in the cabinet and a VERY non resonant space (hopefully) on the outside of the cone or horn. Versus... The trumpet/player has a very low resonance space (the body/oral space) before the pulsating aperture and a VERY VERY resonant space outside the aperture (the mp and horn)

So there is no accurate comparison between the two systems.

Also, aluding to Thomas Moore's investigation (already mentioned) the oral space has no noticable effect in his three-phased investigation of theoretical/ simulated / and demonstrated.

The air in the mouth need only be suitably pressurized. (at lung pressure)




Inefficiency? Lower pressure? Not so. The more "wide" the (oral) path is the more pressure is "sustained" thru that path in the pressence of flow. Of course the loss of air pressure due to viscousity (friction) is not appreciable but for all but the narrowest of paths and/or the greatest of flows.

There is nothing more efficient about a narrower path. Again, due to viscousity, it is slightly less efficient. And this inefficiency increases VERY much as the path is made more narrow.

(somewhat compared to an electrical conductor. A "narrow" wire loses voltage (pressure) and energy much greater than a "wide" wire due to resistance. Well a narrow air path also has more "resistance" and pressure and energy are lost due to that.)

But even a variance in the "chamber" of the oral space has negligible effect because of the VERY LARGE resonance on the other side of the aperture. (the horn)


Whoah... You forgot the aperture, which is quite smaller than even a reduced oral space due to the tongue arch, and before the mp.

As with the speaker. A "garden hose" is not a suitable comparison.

Well, the air does flow through the horn. The flow into the mp is indeed necessary due to the "pulses" and due to horn acoustics.

It IS true true that the acoustic impedance of the horn is part of the "resistance" we feel. But this does not increase the pressure. We can only increase the pressure by doing so in the body, namely the lungs and the surrounding muscles of exhalation.

And the upper register is not the only factor of pressure applied. Tone volume is as well.


Essentially I agree with you that speed is simply a "visualization" to coax the player to 1. change the embouchure and thus its frequency of pulsation and 2. to increase the pressure required to sustain flow for a higher pitch.

I would go so far as to say that slower speeds in general would yield greater efficiency. I will have to explain later.

But I think your comparisons to "speakers" and "garden hose" is leading you down a wrong path if you want to accurately understand the system.

Darryl Jones P.E.

MySpace.com - Darryl Jones - Trumpet - PELHAM, Alabama - Jazz / R&B - www.myspace.com/darryljtrumpet

nordlandstrompet

Mr. Jones

Welcome to the forum

I have been a part of this discussion, and posted a couple of ideas about how the air passes through the horn. My conclusion has been that the air flows at different speeds through the lips, mouthpiece, tubes and belltube.
The idea I have tried to explain, has been that the air flows with the same amount through the whole instrument, but changes to higher/fast speed when passing narrow points at its way. There is an attachment in one of my earlier posts which is trying to clarify what I am trying to explain. Do you have any idea if this "venturi suggestion" is a good explanation?

oldlips48

OK, let me see if I got this straight....

If I fill my mouth with water from a garden hose and blow into my horn with my tongue pressed up against the back of a loudspeaker while the bell of my horn is blowing bubbles into a carbeurator, my lips will vibrate like guitar strings and produce that oh so elusive triple C!

the piano is looking better all the time......

Adam Smith

haha. I think youve got it!!

Schilke player

I've seen this page. I think it has the right idea. It doesnt tell you how to increase the pressure in the "air tank" though. You may want to check out Bbtrumpet.com. Theres a book for sale there that tells you how to do it.

kalijah

Nordlands wrote:

Yes, the air flow is constant through the system, from lungs to bell. (With a minor exception)

And the speed can be determined anywhere by considering the cross section.

But you must be careful that you understand that because the air is "faster" through a narrow segment, this does not mean that the air has more energy due to this increase in speed due to "narrowing".

And it also becomes evident that the greatest velocity is through the aperture.

Also, increasing the narrowing anywhere in the system before the mp cup also increases the resistance and would yield a smaller flow for the same pressure. But usually not much less for most normal actions of tongue arch.

For example, tongue arch proponents make the claim that arching the tongue "speeds up" the air and the resulting "faster" air yields a higher pitch.

There are two faults to this way of thinking:

1. Arching the tongue will never increase the air energy at the aperture (total pressure) above what the lungs provide. and..

2. The pitch will not change unless the aperture pulsation frequency changes. The aperture itself must change. Namely, become smaller, to ascend.

kalijah

These sites are really in the visualization realm. And should be taken as such. The problem is... What if I am playing a high note softly, does this still require "super fast" air?

No.

What if I am playing low VERY loudly, is is safe to assume that the air is relatively very fast?
Yes.

The concept of "Fast air" to play high notes is really a product of "hearsay", it is a popular myth. The is much more to playing high musically than simply "jetting" air. Even though that IS a visualiztion that some use as a PART of learning.

nordlandstrompet

You can't let the bell blow bubbles into the carburator.
The bell is the exhaustpipe, and your equipment will not be able to start if you do that .
Except from that, your interpretation seems ok.

nordlandstrompet

Thanks for your clarifying answers.

Visualition and metafores has always been a efficient way of telling people how to act. This is also a reality for non brassplayers.

Ok. Next level:

Airflow: "The air is only active until it has left the lips. After this point, it lives its own life, (more or less inactive) inside the instrument, but follows some physical laws?"

rowuk

Kalijah,
I don't believe that I am confusing anything, but you are right the non-technical explanations are not adequate for anyone that really knows the physics.

My speaker comparison is with a (resonant) front loaded horn system that does share many of the traits of the trumpet. There is a technique called reactance annulling that provides "equal" pressure to both sides of the speaker cone, definitely a technique used with certain embouchures where the lips may not protrude into the mouthpiece as it is very shallow. That annulling requires a small chamber.

The comparison of the electrical conductor is a stretch as the cross section of the breathing apparatus is very diverse. A wire with big changes in diameter is essentially only as good as the thinnest part. If we want to introduce wire, then we have to look at its RF properties, which compared with trumpet behavior at audio frequencies, is all over the place. The big oral cavity acts as a low pass filter - reduces high frequencies, makes tone darker. This qualifies as a "less efficient" system in my book. Getting back to speakers, Bose uses a similar technology in their acoustimass woofers - albeit at much lower frequencies.

In any case, I think many of our readers got the message that:
1) the trumpet is a complicated beast
2) fast air is not true
3) the search for efficient playing is a much more useful goal!

I am very interested in your idea about "slower speeds" being more efficient.