Air Stream - Speed or Volume
Updated: Apr 17, 2021
THIS post might be a little controversial, but I assure you, it is based in physics and collected data, data collected by the late great Arnold Jacobs, no less. However, there should really be no controversy, as, in the end, this is all about semantics and linguists used to achieve a specific result and that is playing trumpet a little bit better.
Over the years I have had conversations with many fine trumpeters and trumpet teachers who talk about "moving the air" or "use of compression" or "high velocity air" and many other expressions. One of my favorites was "fill the horn with air!" Hmmmmm... I thought the horn was filled with air when I took it out of the case. As a student, I had difficulty making sense out of all of this. I was burdened with the fact that at the same time I was really beginning my study of advanced trumpet technique, I was also studying electrical engineering and applied physics, so I was having trouble making the two "languages" fit together. In this blog I hope to help provide some translation between those two languages.
Note: I am NOT going to address a lot about the physiology of blowing (like blowing with the diaphragm muscle). I think, you can just Google that info and be just fine.
Most of my discussion will be based on two resources: my studies in acoustics (I'll try to bring some books into play with some line cites) and an article published in the 2012 ITG Journal. Here is a title and link to that article. You should definitely read this!
I do have another blog post on this subject about using wind, and I would suggest reviewing that as well. I have a link to my bubble demo video in there.
In this article they refer to INTRA-ORAL PRESSURE, which is the air pressure, which is the air pressure INSIDE THE MOUTH JUST BEHIND THE EMBOUCHURE. The units of measurement in the metric system would be Pascals, but most non physics folks might relate to psi or pounds (a unit of force) per square inch. They also refer to onset pressure which is the minimal amount of intra-oral pressure needed before the note is commenced.
Another relevant measurement is airflow, of the volume of air moved per second. The metric units would be liters per second, but we all can relate to liters, these days.
In 1959 and 1960 Arnold Jacobs conducted a great deal of research into how we blow horns and collected a great deal of data. Much of that info is cited in the article mentioned above. I am simply going to interpret the specific sections I highlighted in my reading of the article in preparation for some lecture interviews.
So, I will assume that I have piqued your interest enough, at this point, to read that ITG article. It is fascinating and illuminating. From here on on I am essentially going to list MY "takeaways" on the article and how I use them in contemplating my own progress as a trumpeter.
There is an inverse relationship between airflow and intra-oral pressure. The highest note in the study (D4) produced the lowest airflow but required the highest intra-oral pressure.
This fits my discussion in my bubble video. As I play in the upper register, the amount of air I flow through the horn goes down, but I have to pull my abs and lower back muscles in to keep the pressure up as opposed to moving more air through the horn.
This reference is found on page 13 of the ITG article at the top of the first column.
Pressure and resulting air flow are established about .05 seconds before the release of the note.
I took some lessons from Bobby Shew and we discussed his wedge breath. I also have a copy of his notes "Chops and Changes." He discussed a brief hold (of breath) a split second before we let a note go. The data shows this to have merit.
This did bug my classical trumpet teachers a bit who insisted that that we never hold our breath before we play as it foments tension in our playing.
According to the data, which was independent of playing style, this occurs with all players. I do believe the language can be reconciled though.
I believe the classic approach is addressing the idea of literally holing your breath for a few seconds before you play. Shew, from my recollection and interpretation of his notes, was not advocating for that. A slit second "hold" would seem to be addressing the .05 seconds discovered in the data.
The reference discussed here can be found on the same page (13) a little further down.
It is possible to play different notes in a series with the same intra-oral pressure but different levels of loudness.
This is a little odd to contemplate, but it boils down this: intra-oral pressure is not related to pitch unless loudness is held constant. Intra-oral pressure is not necessary a cause of moving to a higher note.
This discussion on on page 14 of the article.
Players tend to play more loudly as they ascend in pitch.
This is rather obvious, but I found in interesting that the data analysis bore that out. This is on page 15 in the second column.
This one is quite important to me, so I will do a direct quote from the article.
"In the world of brass pedagogy the discussion of air flow rate can frequently be a source of miscommunication. That a brass player perceives of as greater air flow is not always directly correlated to an actual greater volume of air passing through the instrument." (page 15, second column about midway down).
Continuing a little further down...
"So, because perceived air flow is not the same as actual air flow, it is often the case that a brass players or teachers who relate that they are consciously moving more air through the horn may in fact be moving a great deal less than the student they are addressing."
This means a lot to me when it comes to reinforcing my own thinking as it applies to my own personal progress, that I should not necessarily be focusing on moving "more air through the horn." That may be a useful metaphor to some, but for me, since I can't disconnect from the physics, the ideas of the article line up with my thinking better.
In the study cited by the authors, the trumpet had the highest airflow of all the instrument discusses (which might a a surprise to bass trombone or tuba players) had the least intra-oral pressure.
At this point in the article, the authors go in a lengthy technical discussion about why this is. I invite you to read it, though this diversion has a slight flaw from my understanding of the physics involved. They refer to resistance as being controlled by the embouchure. Then they refer to "tension" as the only factor in adjusting the resistance.
I am not on the same page with the authors on this. The so called "lip aperture" (the size of the hole formed between the lips when they pop open to the maximum size in the vibration cycle) changes with pitch. Lower the vibrating mass by making the aperture smaller drives the pitch up. In fact, it can be argued that the vibrating mass has more impact on the pitch than the tension.
On page 17 they loosely comment on vibrating mass in the first column near the top as having some impact on timbre, but they don't really go into any detail on how vibrating mass can affect range. Perhaps in another article.
This one is a bit of a hot potato. I think a direct quote is in order.
" Frequently, brass instructors give their students instructions on how to achieve greater success by modifying the stream or column of air. These modifications include such metaphors as thicker air, faster air, slower air, hissing, raise or lower the tongue, etc."
I have sued a couple of these myself - tongue arch, hissing, etc. I have never used thicker air and have always avoided faster or slower air.
A little further down the same (first) column: " ...unless taken to extreme, all of the aforementioned air modifying systems (as well as many others) have very little effect on intra-oral pressure and subsequent airflow."
Here are my thoughts (again, as they relate to my own personal progress) on this. I have no problem with the idea that tongue position might not affect the intra -oral pressure or airflow. I have never even considered this when deploying those methods. I DO believe they have some impact on the resonant system, and therefore can have some impact on the range and/or the ability to gracefully shift between harmonics (think lip trills). So, I don't think all of the metaphors are without merit.
The idea of tongue position (oral cavity being a necessary side discussion) is a controversial one and will the the subject of another blog.
This one comes from footnote number 13 in the article. Read it, but I will interpret here.
They comment on the fact that the tongue position can have an effect on the notes played IF you isolate the air column from the back of the tongue with to the lips. I actually include this in my "mouthpiece-horn squeaks." I am essentially just squeezing the air out of my MOUTH only with my tongue. I can achieve extreme upper register this way. By extreme, this is how I can play triple high C's, for what they are worth.
However, if I try to relax the "glottis" and let my lungs enter the fray with the abs pressuring the system, those extreme high high notes are quite tough to maintain. The comments in their foot note #13 fits, but the why of it isn't addressed. Again, this will be part of another blog.
The trick is to just allow the glottis to "leak" some air into the oral cavity without completely reconnecting the entire lung volume to the system. It can be done.
That is about it for this week's blog. I hope it makes sense. More importantly, I hope you see how I am trying to sort things out for myself. It is more important to me that you walk away from my blog with an inspiration to check out the article and make sense out if for YOURSELF. I am most certainly not trying to convince you that my way of thinking is the only way.
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