Singers have a well-codified system of vocal phonation modes that may parallel sound production for the brass player. Study of these modes may help brass players produce sounds that are more resonant and more colorful.
Brass players and singers have much in common. For both groups, an actual part of the human body produces the sound. For the brass player, it is the lips; for the singer, the vocal cords. In both cases, flesh is activated by the flow of air, and the faster the oscillation of that tissue, the higher the pitch. In both cases, the diaphragm, thoracic, and abdominal muscles modify the respiratory system's natural process. The sound of a singer's vocal cords vibrating prior to passing through the oral cavity sounds quite a bit like a brass player buzzing their mouthpiece. (Steenstrup, 18)
Singers have a long and robust tradition in exploring the science of sound production, a tradition that in some ways is superior to what we know about sound production in brass instruments. For today's blog article, I would like to focus on some basic ideas of vocal sound production, and how they might inform our thoughts about brass playing. In particular, I would like for brass players to explore how they may be able to develop and explore new tone colors, in a similar manner to how singers do this with vocal phonation modes.
For starters, four principles regarding sound production for singers should be noted:
1. The vocal cords are a singer's reed, and they consist of the thyroarytenoid muscle and a membrane that covers it.
2. Adduction is the "closing" movement of the vocal folds, coming together.
3. Abduction is the "opening" movement of the vocal folds, separating apart.
4. The sound quality (timbre) is largely derived from the balance of opening and closing phases. If the closing phase is longer than the opening phase, the sound will be brighter (richer in upper harmonics). If the opening phase is longer than the closing phase, the sound will be darker (lacking in upper harmonics).
(For a more in-depth explanation of harmonics and tone color, check out the video I made last year on this subject.)
Process of Phonation
The phonation process involves the opening and closing phases of the vocal cords in response to the air, in a manner quite similar to that of the brass player’s lips. Since I am not a singer, allow me to directly reference a well-respected vocal pedagogy source: Agostoni writes:
“During the expiration the vocal cords are drawn together by the adductor muscles; the subglottic pressure pushes them apart, while their elastic recoil and the decrease of the lateral pressure due to the increase in kinetic pressure (Bernoulli principle) close them again, thus generating a periodic flow.” (Agostini, 105–106)
Types of Phonation
Vocal phonation is the process by which the vocal folds produce sound. Vocal pedagogues know that the timbre of a singer’s voice is determined by the type of phonation they employ. In the standard voice pedagogy textbook, The Science of the Singing Voice (1987), Johan Sundberg introduced four types of phonation: breathy, pressed, flow, and neutral. Since that time, other modes have been described, such as creak phonation and falsetto phonation.
Breathy phonation is when there is a higher airflow (and according to Boyle’s law, inversely, lower air pressure) and a low adduction force. A great deal of air passing between the vocal folds that are held together by a smaller adduction force means that the vocal folds likely do not come completely together. This causes air to pass over the vocal folds that is not used for vibration, but rather, is heard as noise. Therefore, the unvibrated “noise” is perceptible in the sound quality, leading to a “breathy” timbre. This timbre of breathing phonation has a lower intensity of the upper harmonics.
Substituting "lips" for "vocal cords," and keeping the air in common, we can conjecture a brass playing equivalent of breathy phonation. Indeed, brass players get an airy sound, lacking in upper harmonics, when lips do not come completely together. Said another way, an airy sound may be the result of a lack of muscular contraction of the lip muscles and/or an aperture that is too large.
My friend and former University of Kentucky trumpet professor Vince DiMartino sometimes uses the term "blow-by" to describe this phenomenon for trumpet players -- Air that passes between the lips unvibrated and is heard as noise. It would seem to me that the “DiMartino Blow-by” and traditional vocal breathy phonation have much in common.
Another vocal phonation mode is pressed phonation. If the vocal cords are pressed together with a high adduction force, combined with a higher air pressure, the closing phase is longer than the opening phase, which would result in a stronger intensity of the upper harmonics, which may be perceived as a "strident" or "bright" sound.
The brass playing equivalent of pressed phonation could be considered to be the strident sound, strong in upper harmonics, that results from the combination of lips that are pressed very tightly together, with high air pressure.
Flow Phonation (also called Resonant Phonation)
Flow phonation is the most resonant method of vocal phonation. Characteristics of flow phonation include high airflow, and a high but balanced subglottal pressure. Flow phonation is the most desirable method of singing and results in a balanced spectrum of harmonics.
The brass playing equivalent to flow phonation could be when airflow and lips are working together, perfectly in balance, to produce the most resonant sound quality.
Other Modes of Phonation
Vocal pedagogues also describe other modes of vocal phonation. Creak phonation is when there is a strong adduction force but at a very low frequency; this is the result of irregular oscillation. This is also known as “vocal fry.” Falsetto phonation is where the vocal folds are stretched and the vibrating surface is quite thin; this results in much higher pitches. (I’m not sure if there would be a direct equivalent of this phonation for brass players, but it sure would be nice if there was a quick way to pop up the octave!)
While “flow phonation” may be the most ideal method for producing a resonant sound, singers may intentionally use other modes of phonation to change their vocal color, for expressive purposes. A singer may use breathy phonation for a breathy, intimate timbre. A singer may use a pressed phonation to achieve a tense, strident sound to convey anger.
Similarly, while brass players should also strive for physical efficiency and their most resonant sound production, they should also explore methods for producing a variety of tone colors. Changes in airflow, air pressure, and adduction force can also yield changes in a brass player’s timbre. For example, a jazz trumpet player may purposely allow some air to enter their sound to obtain a more diffused timbre. Conversely, a brass player may press their lips together with a high adduction force in order to create more upper harmonics in their timbre.
Changing to Stay The Same
Another important thing brass players can learn from singers is the importance of changing to stay the same. Since the amount of air remaining in the lungs is constantly decreasing over the course of a musical phrase, the relationship between airflow and the vocal cord tension is constantly changing. Agostini writes,
“To produce a pitch of constant loudness and pitch the subglottic pressure must increase, while the vocal cord tension must decrease in order to keep the pitch constant.”
For brass players, a takeaway is that maintaining a note of the same volume and pitch is not a static process, but rather one in which we must change in order to stay the same.
Focus on the Music, Not on the Muscles
One conclusion that could be drawn from this information is that more focus should be put on the musician's specific control of their musculature -- but nothing could be further from the truth. Singers should not attempt to directly and mechanically control the stiffness and tension of their vocal cords. In the same book that codifies vocal phonation modes, Sundberg writes,
"We do not need to bother about the extremely complicated maneuvers we perform. We just perform them unconsciously, and what catches our attention is the end result, the sound." (Sundberg, The Science of Singing Voice, 18)
In a similar way, brass musicians need not worry about the specific musculature involved when they are performing. Rather, this information can be used as a diagnostic tool to address and correct problems.
Good Playing is Easy
My teacher Keith Johnson would often say, “Good playing is easy,” and I believe the singer’s concept of flow phonation reinforces this notion. Since vocal flow phonation is achieved through less contraction of the laryngeal muscles and less air pressure, it could also be described as the type of sound production that requires the least physical effort. Said another way, the most resonant sound quality may best be achieved through a method that is also the easiest from a physiological and aerodynamic basis.
For Future Researchers
While these phonation modes have been well researched by vocal pedagogues, more work is needed in the area of brass pedagogy. I believe there are many parallels between singing and trumpet playing, and this is a golden opportunity for future researchers. Ambitious and creative doctoral students who may be reading this blog may find this an area not yet adequately explored by brass researchers, and quite possibly a great topic for future dissertation and scholarly article work.
The author would like to extend a special thank you to Dr. Elizabeth Arnold, Associate Professor of Voice in the University of Kentucky School of Music, for her contribution to and feedback on this article.
Jason Dovel is associate professor of trumpet at the University of Kentucky and a Yamaha Performing Artist. He is host of the annual UK Summer Trumpet Institute held every June in Lexington, KY (USA).
Sources/For Future Research
If you'd like to take a look at what vocal cords look like "in action," check out this YouTube video: https://www.youtube.com/watch?v=D6mLc9gOgVA
Modes of Phonation Website: https://www.vocalovertones.com/modes-of-phonation/
of Phonation (With cool sound files for examples):
Dovel, Jason, Exploring Trumpet Tone Color, https://youtu.be/94E5HewSWQY
Agostini, E and Ambrogio, G. Sant, The Respiratory Muscles, Mechanics, and Neural Control, 1970.
Proutskova, Rhodes, Crawford, and Wiggins, "Breathy, Resonant, Pressed - Automatic Detection of Phonation Mode from Audio Recordings of Singing," Journal of New Music Research (2013)
Steenstrup, Kristian, Teaching Brass (2nd revised edition), Royal Academy of Music, Aarhus, 2007.