Air Flow, Transducers, and Sound Efficiency in Brass and Vocals

This month, I’m focusing on my trombone and euphonium playing for my album. It’s a very perishable skill that requires physical conditioning, so I’ve been practicing for a while to literally get back in shape. But even now, nearly 9 years removed from Music School, I’m learning new things.

Writing this album has taught me a lot more than I expected it would. I undertook the project partly because I knew that I needed some sort of a challenge in order to progress my abilities. I anticipated learning more about songwriting, arranging, audio mixing, and the legal and distribution processes. What I didn’t anticipate learning more about is how vocal cords and brass instruments resonate, and how air flow affects them both similarly.

**Disclaimer- Today’s post is going to be dry and technical. It will be incredibly boring to most people, and interesting to some**

I got started thinking about this about a year ago. In my Air National Guard Band, we have an incredible trumpet player, Ben Peterson. He’s a true renaissance man, and I always enjoy getting the opportunity to pick his brain during drill. He wrote a book (which I haven’t read) on the acoustic physics of the trumpet and how to apply them in practice. Check it out here:

Fundamentally, the trumpet is no different than any other brass instrument (I play the trombone and euphonium, which are brass instruments), so the acoustic properties apply to me as well. For anyone who doesn’t know how the basic acoustics work on those things, I’ll sum it up. The sound is first made by the player buzzing their lips, and they control the pitch by the tension and aperture size of their lips. The horn is a designated volume of air, and by either pushing valves or moving a slide, the volume of air inside the instrument changes. This air volume difference affects what frequencies the instrument will resonate at. When the frequency of the lip buzz matches the resonant frequency of the horn, it makes a nice sound. If the two frequencies don’t match, it sounds bad.

So, all through my brass-playing life, I’ve been told, “Use more air,” or “You need faster air to play higher notes,” or “More air equals more sound,” or “Fill the horn with air,” or “the air should be free-blowing,” and a hundred other statements to a similar effect. The idea I had in my head through this teaching is that I am creating a column of resonating air inside the instrument, and in order for the sound to project correctly, I have to push the air through the instrument with powerful diaphragm muscles. That is a common school of thought, but it’s absolutely not how acoustic physics work.

The concept that Ben Peterson pushes is very much the opposite. It actually takes very little air to put your lips into a buzz. The aperture created by pushing air through a lip buzz is a very small opening. It opens more on lower notes, and shrinks on higher notes. If you try to blow a lot of air through a small opening in your lips (try it real quick), you’ll quickly realize that your head, neck, chest, and/or stomach is having to push really hard to get that air through that tiny hole. Now make a larger opening in your lips, about the size you’d use to whistle (simulating a very low note). This feels much more “free blowing” and free of tension. But nobody is playing low notes all the time, except tuba players. So the commonly taught idea of “more air for higher notes” now makes complete nonsense.

So let’s call the lips in brass playing a transducer. In audio speakers, a transducer is the device that converts electrical signals into mechanical energy/vibrations that make sound. Similarly, the lips convert the energy of the air flow into sound. In a speaker, it’s usually more ideal to have an efficient transducer. If you look up specs on professional speakers, they’ll always have a “sensitivity” rating. The sensitivity is how many decibels the speaker will create (measured at 1 meter away) if it’s given just 1 watt of electrical power. A sensitivity around 96dB per watt is pretty normal for a loudspeaker. That’s a good deal. It’s enough to fill a hotel ballroom decently with only 1 watt of electricity. Each time you double the wattage, you gain 3dB. But the speakers have their limits. 500 Watts RMS (continuous input) is a common average limit, but they can handle brief peaks of up to 2,000 watts for a few milliseconds without sustaining damage sometimes. So the wattage rating listed on your speaker is describing the physical limits of what it can bear before damage occurs.

The lips and the vocal cords have their energy limits as well. But because our bodies are not machines and are more easily subject to exhaustion and degradation, those energy limits lower throughout performance time. Pushing a lot of air is like pushing a lot of electrical energy. A well-conditioned musician’s lips or voice may be in really good physical condition with strong muscles and substantial endurance. This is like having a speaker with a high wattage capacity. Since they are muscles, you can build that strength through training (or some people just have good genes and can sing loud without effort). But both the lips and the vocal cords require only a tiny amount of air flow to sustain a pitch, just like a loudspeaker can create 96dB of sound with only 1 watt of electrical energy. Regardless of the caliber of musician, their voice or lips will get tired after a time, and the threshold for the amount of air energy they can continue to control lessens.

So then we arrive at the question, “How do you make lips or vocal cords more efficient?” It’s certainly something that I haven’t mastered, but I’m working on it. I’m in the process of developing warm ups and exercises that focus on air efficiency. (Contact me if you want to talk about those). But there is a guy who has mastered this. One of Ben Peterson’s teachers, Jim Manley. He plays jazz around St. Louis, most regularly at Sasha’s Wine Bar. Check out this video that sums up some of his concepts:

His playing concept centers around letting the resonance of the horn do the work of amplification, while the player keeps the air flow as little as necessary. If you pump too much air/energy through your lips, just a like a speaker hitting its limits, your lips will get tired and burn out because they’re trying to work harder to restrain and control the superfluous amount of air. It also creates tension in the rest of your body. And tension causes a ton of other issues like bad tone, bad tuning, shaky tone… Jim Manley can play high notes for hours with very little fatigue. Contrast his philosophy with the widely idolized trumpeter, Maynard Ferguson:

There’s nothing wrong with this, but unless you’re young Maynard, you can’t play like that for hours. Especially not in Sasha’s Wine Bar.

I started putting this stuff together just a few weeks ago after I had a voice lesson with the talented Gina Malone, principal soprano for the St. Louis Symphony Chorus. For Christmas, Lindsay bought me 2 voice lessons with her. We covered a LOT in our first lesson, and I was rigorously taking down notes.

Here’s a link to Gina’s teaching business:

We talked a good amount on breathing deeply, minimizing tension, and exhaling a certain controlled way. One thing she had me do was sing through a straw. She does this in her own practice to ensure that she is being efficient with her air flow. Through the straw, I sang an exercise starting on an F below Middle C, working my way upwards. When I got to the Middle C, my voice did this crazy thing and I could not sing the note. My voice involuntarily made a gurgling Chewbacca sound, I don’t know how else to explain it. My first thought was that maybe the straw’s resonate frequency was clashing with my voice, but when I took it back to practice, I figured out that it was something else. I was using more air to sing higher… just like I was taught throughout my life in brass-playing. The straw’s width was not large enough for a free-flowing capacity of air to come out of it. This caused backwards air pressure going back into myself, causing the gurgle effect. I practiced singing higher softer and with less air and found that I had better control over the tone and pitch when I withheld some of the air flow. It’s the opposite of trying to manhandle the sound, which is what I’ve always previously inclined to do.

To sum it up, pushing or allowing the air to come out too fast is inherently inefficient and causes other issues with body tension and back-pressure. On the euphonium, if the tone of my lip buzz is efficient, and the pitch perfectly matches the resonant frequency of the instrument, it’s easy to get 95dB of sound with nearly 0 effort (yes, I measured). That’s loud, and it’s not too often that I’d need to be louder than that. Let the instrument do the work. When it comes to the voice, I still have a lot to learn.

I’m not nearly as informed on the mechanics of the vocal cords as I am on lip buzzing. It’s a subject I’m still learning about, so please don’t take my vocal advice 😉

Thanks for reading! Til next week, folks.

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