Seeing the Unseen: Trombone Playing Through the Eye of a MRI Scanner with the MRI Brass Repository Project

Seeing the Unseen: Trombone Playing Through the Eye of a MRI Scanner with the MRI Brass Repository Project

by Douglas Yeo

While individuals have been playing musical instruments that require vibrating lips to produce sound since before the dawn of recorded time – we need only think of the shofar, didgeridoo, and conch shell to begin a list of lip-blown aerophones of ancient origin – there is much about playing such instruments that remains a mystery. Whether thousands of years old or made last week at a modern brass instrument factory, the fundamental changes to brasses over the millennia have been those of material, construction and ergonomics rather than actual tone production. As every school child that has ever picked up a trumpet, trombone, horn, euphonium or tuba knows, all that is needed to create a sound on a brass instrument is to place one’s lips on the mouthpiece, vibrate the lips by passing air through them, and, Voilá! Another brass player is born.

Yet while trombonist and Boston-based brass pedagogue John Coffey (1907-1981)  summarized his teaching with the pithy phrase, “Tongue and blow, kid,” successful brass instrument articulation and tone production actually requires a bit more understanding. Teachers and performers have written legions of books and articles about what players should do with their tongue and other members of the body’s oral cavity, but such descriptions have been hampered by an obvious problem: we cannot see inside the mouth or touch the tongue, glottis or soft palate while playing. One’s tongue cannot touch one’s tongue in order to feel one’s tongue when it is in use. It is clear that much of what has been said about the workings of the tongue during playing has been nothing more than well-meaning conjecture.

In 1897, Harold W. Atkinson summed up the difficulty that researchers faced when attempting to describe tongue’s position while speaking:

Their descriptions, accompanied or unaccompanied by diagrams, as the case may be, vary in those points of detail which are beyond the range of comparatively easy determination. This has been due, it would appear, to lack of suitable methods of measurement, more than to a lack of enthusiasm on the part of observers. Though equipped with the necessary anatomical and physical knowledge, they have lacked the power of designing appropriate methods or apparatus for making exact measurements.[1]


“Tongue measurer” by Harold W. Atkinson (1897)

Atkinson’s solution was to devise a “tongue measurer” made of silver, a delicate, movable wire with a “tooth stop” that slid up and down the wire. Inserted into a subject’s mouth – a reasonable person might immediately exclaim, “Not in my mouth!” – a syllable was spoken, the tooth stop moved, the wire was then applied to a plaster of Paris model of the mouth, and measurements taken. Professor Atkinson can be commended for his desire for understanding as well as his ingenuity, but his methodology was inexact at best.

For low brass players, we have long been accustomed to hearing wisdom about the use of the tongue and throat from some of the finest players and teachers of the twentieth century. Yet words and sentences often are used in murky ways that lead to misunderstanding and confusion. We are used to encountering phrases like:

“. . . The throat should be entirely free of resistance. . . the tongue should be loose and relaxed.”[2]

“Physical law provides that the embouchure is the determiner of pitch, so why should the tongue get so involved. . .?”[3]

“The throat should always be relaxed.”[4]

“It is important that the tongue remain as relaxed as possible at all times. . .”[5]

“Many brass players react in horror when I suggest using [the glottis] for purposes of playing our instruments.”[6]

“However, especially with the euphonium and tuba, the tongue is never positioned ‘high’ in the oral cavity, even in the upper register.”[7]

“Correct tonguing is an up-and-down motion. . .”[8]

But what exactly is “the throat”? What part of the tongue should be “loose and relaxed”? Is the glottis at work when doing a crescendo or diminuendo? Should it be at work? What is the glottis, anyway? Does the tongue have a role in determining pitch? Is correct tonguing an up-and-down or a back-and-forth motion?

Confusion continues when authors write suggested vocal syllables that players should keep in mind while playing. “Open” syllables are often spoken of as being preferred to “closed” sounds (there we go again, using words that we haven’t clearly defined), but when one reads the syllable “AY” in print, is that “AY” as in “hay” or “AY” as in “aye”? When one sees the word, “TOO,” is it to be thought of as “two” or “toe”? Should the tongue ever be allowed to rise up high in the oral cavity with the syllable “TEE” or should the tongue always be kept down and low in the mouth while using the open sounding syllable, “TOH”?

These authors quoted above – including this writer – can hardly be blamed for doing their best to describe a complex subject with limited actual understanding with which to work. X-ray vision is the stuff of Superman, not trombone teachers, and the intuitive description of the operation of the tongue by many writers has seemed to be reasonable, if unproven. Yet with the advances of modern medical diagnostic techniques, brass players, teachers, and scientists are coming together to show us what has hitherto been impossible to clearly see: the operation of the tongue and associated organs inside the mouth while playing a brass instrument in real time.[9]


Begun in 2013, the MRI Brass Repository Project (MBRP)[10] was conceived by Dr. Peter Iltis, Professor of Kinesiology at Gordon College, Massachusetts. Iltis’ interest in the physiology of the brass player’s embouchure and associated parts of the oral cavity led to his collaboration and partnership with Dr. Jens Frahm, Director of Biomedical NMR Research at the Max Planck Institute for Biophysical Chemistry in Göttingen, Germany, and Dr. Eckart Altenmüller, Director of the Institute for Music Physiology and Musician’s Medicine in Hannover, Germany, to create the MBRP.[11] The Max Planck Institute has generously provided use of their magnetic resonance imaging (MRI) scanner, a non-invasive tool that allows subjects to be tested without time limitations or exposure to harmful radiation.


Left to right: Jens Frahm, Douglas Yeo, Eckart Altenmüller, Peter Iltis

The MBRP’s work started with testing of elite, college/conservatory, and embouchure dystonic horn players, using a horn bell made and donated by Rick Seraphinoff (Bloomington, Indiana). Those studies led Iltis and his team to report their preliminary findings in numerous articles in peer-reviewed scientific journals and music publications,[12] as well as in several web-based video interviews and podcasts.[13]

Normal playing of a brass instrument inside a MRI scanner is impossible; there is not enough clearance in the scanner to allow movement of a trombone slide or for the hands of a player to operate valves. Additionally, no ferrous metal can be in the scanner room because of the powerful magnets that are used to create the MRI images; therefore, non-ferrous brass bells must be constructed. A brass instrument bell is then connected to plastic tubing and a plastic mouthpiece, and a player inside the scanner can play notes in the overtone series while the playing is video recorded in sagittal (from the side of the head) and coronal (from the front of the head) views at 55 frames per second. Exercises involving double tonguing were recorded at 100 frames per second in sagittal views. In this way, the workings of the oral cavity during brass playing be observed in real time, and the movement and use of the tongue, soft palate, and glottis can be carefully examined.


Having tested a large cohort of horn players, Peter Iltis asked me to lead the study of trombone players. This involved my writing a protocol for trombone players to play inside the scanner, and also traveling to the Max Planck Institute in Germany to be the pilot subject in the trombone study. This I did in April 2017. My goal in writing the trombone protocol was to devise exercises that would help us to understand various aspects of trombone playing. In particular, these involved tonguing with various types of articulation, single and double tonguing, slurring, air attacks, and pitch bends. I was also interested to see how the tongue moved while whistling, since the action of the tongue while whistling is often used as a metaphor for tongue placement in various registers of brass playing.


Jens Frahm and Peter Iltis with specially made non-ferrous tenor and bass trombone bells, designed, manufactured and donated by YAMAHA Corporation (Hamatsu, Japan)

YAMAHA Corporation (Hamamatsu, Japan), designed, manufactured, and donated specially made non-ferrous tenor and bass trombone bells for the study, and Kelly Mouthpieces also donated several plastic trombone mouthpieces for use by players. I also experimented with several types of flexible rubber/plastic tubing (clear, reinforced, PVC, etc), which I had collected in a variety of bore sizes including reasonably standard trombone bore sizes of .500, .550, and .562 inches.

I was familiar with how an MRI scanner worked due to my having had several MRI exams over the years in preparation for various surgical procedures. Those exams involved the taking of still images, and the operation of the MRI scanner’s magnets created a loud, banging sound. However, the scanner used in Göttingen did not make this kind of sound. Rather, the machine made a loud, constant, high-pitched whirr over which I was able to hear myself play the trombone fairly well, despite my wearing earplugs. In addition, as I lay prone on my back in the scanner, my head was gently cradled inside a helmet to help keep my head from making unnecessary movements.

Those who have been inside a MRI scanner know that it can generate a feeling of claustrophobia. Once one is moved into the scanner, one’s nose is only a few inches from the top of the scanner tube. The Max Planck Institute developed an innovative solution to the claustrophobia problem. A double mirror was affixed to the helmet at eye level so when I looked up, I had the impression of looking into the room; this gave me the illusion that I was not in the scanner, but rather I was sitting in a chair looking at my surroundings.

In all, I was in the MRI scanner for two hours and I recorded 57 exercises. Here follows some of what we learned, drawn from 11 selected videos.

Video 1 – lip slurs


[This video may be viewed on YouTube by clicking HERE.]

A good place to start is a simple lip slur exercise. It should be said at the outset that during the time I was playing all exercises inside the scanner, I attempted to follow the advice I learned from Edward Kleinhammer[14] as a student: keep the tongue down and the throat open at all times, in all registers and in all dynamics. As he would simply say, “Yawn, don’t cough.” This was a core tenet of Kleinhammer’s teaching, expressed in his books The Art of Trombone Playing and Mastering the Trombone, and it is a central part of the pedagogy of many trombone teachers and players. My only regret associated with the MBRP is that Edward Kleinhammer did not live to see it come to pass. Knowing him as I did, I know that the process, its outcomes, and conclusions would have fascinated him.

As you view this video, you will first see me swallow several times. What happens when we swallow? The tongue arches upward in the oral cavity and presses both against the roof of the mouth as well as backwards. The larynx – what is popularly referred to as the “Adam’s apple” – is pulled upward to allow the easy passage of saliva into the esophagus. In addition, you will see a small flap of cartilage called the epiglottis move over the trachea (wind pipe) so saliva goes down the esophagus; this prevents a person from choking when saliva goes, as is often said, “down the wrong way.” Also, selected muscles of the oropharynx (what we typically refer to as “the back of the throat”) constrict to aid in pushing saliva – and food – downward.

On the far left edge of many of these videos, part of my thumb that was supporting the mouthpiece can be seen; keep in mind that the mouthpiece was plastic so it does not appear in the MRI images. As I inhale, observe that my soft palate is open at the top of my oral cavity. This closes as I transition from inhaling to playing so air from the oral cavity goes only into the mouthpiece and is not released through my nose. You will also see that my throat is “open.” That is, the several muscles that work to constrict the oropharynx relax, giving the sensation of an open throat.

As I begin playing, you will observe that as I slur higher, my tongue moves both up and back in my oral cavity. There is also movement below the base of my tongue, with my larynx and glottis – the opening between the vocal cords – moving slightly upward. When I was playing, I felt no sensation of this upward movement in my neck; I always felt that my throat was very relaxed and my tongue was “down.”

Here we see something very important. When we speak of the tongue, we are speaking of an extraordinarily large, strong, and flexible muscle. It does not move as a single muscle in a single direction, but various parts of the tongue can simultaneously move in various directions. There are muscles called extrinsic muscles that act on the body of the tongue to move it up, down, forward and back within the mouth. There are also muscles making up the body of the tongue itself (intrinsic muscles) that can alter the tongue’s shape. As you view these videos, observe the many varied shapes of the tongue as I play exercises with different articulations and in different registers.

As we look at this, we can see that the idea of an “open throat” is something of a misnomer. We can have the sensation and feeling that we are not changing the size of the oropharynx but in fact we are doing so, and doing so seems to be an essential part of pitch production. Size and shape changes of the oropharynx can also be completely independent of the movement of the tongue. Also, the pulsations of air with each note change may very well be playing some role in assisting with pitch changes. From what we have seen, it is already clear that the embouchure is not the sole determiner of pitch, but that the movement of the tongue and work of the oropharynx play an important role in this as well. As I was playing, I sensed that my tongue was low and down in my mouth at all times and that my throat was always “open.” But as we can see, that was not the case. I had to admit: “The tape don’t lie.”

All of these various processes are happening simultaneously and very quickly, and with virtually no thought on the part of the player. To think about all of this as we play would be an overwhelming exercise, resulting in what Arnold Jacobs[15] used to call, “paralysis by analysis.”[16] The reasonable question arises: How can we be unaware of all of these diverse processes despite our concentrating intently on our playing? When I consider this, I am reminded of the words of the Psalmist when expressed his awe of God as the sovereign creator of all things, “I will praise Thee; for I am fearfully and wonderfully made.” (Psalm 139:14) Indeed.

Video 2 – intervals


[This video may be viewed on YouTube by clicking HERE.]

This exercise is a variation on the slur pattern heard earlier. Here, I articulated intervals of the overtone series rather than slur them. These increasingly wide intervals, particularly in the second half of the exercise when I start each group of two notes on a pedal B-flat, show very clearly the different position of the tongue in various registers. And here is something else to notice: observe how I start this exercise. Many players “flick” their tongue forward before playing, not to moisten their lips, but as an absent-minded gesture of which they are usually not aware. I have seen this on MRI videos of other players who are usually surprised to see it. I have always tried to inject as little extraneous motion into my embouchure’s set up as possible, something that, again, came from Edward Kleinhammer. You’ll also see that I have very little movement of my jaw while playing. When I play the pedal B-flats, I do not engage in an embouchure shift. The helmet that I wore in the MRI scanner did not prevent me from moving my jaw; this is the way I ordinarily play as well.

Which leads to these photos:


Left to right: pedal B-flat, low B-flat, tuning B-flat, high B-flat

These four images – still screen shots taken from the videos – show four different notes. From left to right, you see me playing and holding a pedal B-flat, low B-flat, tuning B-flat, and high B-flat. As I play successively higher notes, my tongue changes shape. By the high B-flat, my tongue takes up most of the available space in the oral cavity and the oropharynx has constricted as well. Yet the throat and neck remain relaxed. Apart from a slight firming of my chin, my profile is nearly identical on all four notes.

But . . .

There is virtually no change between the images for the pedal B-flat and the low B-flat. For both notes, the shape, size and position of the tongue is almost identical. The oropharynx is slightly more open for the pedal B-flat than for the low B-flat, but this is a very subtle difference. Both notes show a very open oral cavity. What does this mean? First, we see that my approach to playing is generally very stable. While in the scanner, I simply tried to play the way I normally play, despite the constraints imposed by an unfamiliar instrument and mouthpiece, and the need to play lying on my back. I don’t use an embouchure shift for pedal tones, and the pedal tone seems, as I look at these photos and videos, to simply be a lower sounding note than the note above, and one that does not require a radical change in how the note is made. Absent are any embouchure, chin or oral cavity gymnastics to produce the pedal tone. Second, this shows that tongue placement is not always an indicator of pitch production. While some teachers posit that the tongue has no role in pitch production and that embouchure alone determines pitch, that is clearly not true. On the other hand, the nearly identical tongue placement for my pedal B-flat and low B-flat shows that in the case of these two notes, my tongue was not a significant actor in pitch production. Clearly my embouchure had a greater role in determining the pitch of these two notes, and that is evident when you look at my lips. For the pedal B-flat, my lips are more relaxed, and that is the significant factor that allows me to produce and center that note.

Video 3 – articulated arpeggio


[This video may be viewed on YouTube by clicking HERE.]

Here is an articulated arpeggio that shows the slow, even movement of my tongue as I play notes from lower to higher and then from higher to lower. Again, note the fact that there is only a slight firming of my chin as I go higher, and the tongue evenly rises and falls depending on the range of each note. Observe, too, that when I take a quick breath, my oropharynx is open, allowing me to quickly get in as much air as possible.

Video 4 – slow double tongue


[This video may be viewed on YouTube by clicking HERE.]

Up to now, we have seen exercises that have been slurred or single tongued. Here is an exercise in slow double tonguing. With single tonguing, we have seen that the tongue’s motion is primarily from front to back. But with double tonguing, the “ka” syllable requires the tongue to touch the roof of the mouth in order to form a short, temporary seal that is opened quickly to give the impression of a tongued attack. I don’t ordinarily double tongue at this slow tempo, but it is useful to see how the tongue operates in this kind of slow double tongue action. In this video, we see this slow double-tonguing on both low B-flat and middle F. Even at this slow tempo, I exhibit no “chewing” motion when I am tonguing; I allow the tongue to do its work and the oropharynx is relaxed and open throughout. Many players get very tight when they double tongue. I suspect that is usually a product of insecurity – not feeling one can tongue well – rather than from a physical need of some kind to tighten the neck muscles.

Video 5 – fast double tongue (and slow motion video)

[This video may be viewed on YouTube by clicking HERE.]

Here is essentially the same exercise shown above with several important changes. First, this exercise was recorded at 100 frames per second. Second, I double tongue two different notes, low B-flat and middle F, as fast as possible. Then, after the video in which I tongue each note, part of the same video clip is played back at half speed. As you will see, the movement of my tongue is the same here as in the previous, slow double-tonguing exercise. You will also notice that the oropharynx – the back of my throat – remains open and relaxed. In addition, I perform this exercise in both soft and loud dynamics. I wanted to see if the tongue changed shape depending on the dynamic I used. As you can see, it did not. And even at the loud dynamic, you can see that I kept my oropharynx relaxed.

The previous video showed that the tongue did not change significantly when playing the same exercise softly or loudly. Clearly there are other things at play that affect dynamics. Most teachers and players control dynamic range through intensity of air. But in 1962, Philip Farkas[17] proposed a theory of dynamic control that created a stir among brass teachers. Farkas proposed that the glottis – the opening in the larynx between the vocal cords – could be used as a kind of “whisper valve” to assist in the playing of soft notes. Farkas wrote,

The glottis, being the opening between the vocal cords, is not a tangible thing, but simply the space between these cords, which is completely adjustable in size from wide-open to absolutely shut. Furthermore, although it is involved in the important adjustments used to vary the pitch and quality of the voice in singing, it is used quite naturally and correctly in everyday living to furnish resistance for many purposes, at which times the vocal cords do not sound. For instance, the glottis is completely closed during an act such as lifting a heavy weight. It is exploded open during a cough, or when clearing the throat. It is partially open for whispering, and wide-open for a rapid exhalation such as one would use for a “panting” effect. In this way, the glottis is used as a natural valve, and not for the purpose of vocalizing. I mention the fact that this is a perfectly, natural, everyday function of the glottis, because many brass players react in horror when I suggest using this valve for purposes of playing our instruments. They evidently feel that I am advocating the use of a “tight throat,” a condition all teachers have carefully avoided from the inception of brass playing. To me, the bad habit of playing with a “tight throat” means the forcible tightening of the neck muscles, or worse yet, the sounding of the vocal cords, resulting in a low moaning or groaning noise, heard while the instrument is played, and I have fought these bad habits just as diligently as any other brass teacher. The proper use of the glottis is natural and effective and is quite likely being used by most successful brass players, either consciously or subconsciously.[18]

Here, Farkas proposed something quite radical. While many teachers and players assume that when the glottis closes, the result is a palpable tightness in the throat, Farkas’ examples of how the glottis operates in normal, everyday use, argue against this. Peter Iltis was curious, having tested several horn players on a simple exercise of crescendo and diminuendo, to see if I as a trombone player would show the same tendency that horn players exhibited.[19] And that tendency? To use the glottis as a valve to aid in soft playing.

To show this, the MRI scanner was changed from the sagittal view – taking video of my head from the side – to the coronal view – taking video of my head from the front. With the coronal view, the scanner allowed us to capture images that revealed how the glottis was operating while playing.

Video 6 – glottis, crescendo/diminuendo


[This video may be viewed on YouTube by clicking HERE.]

In this coronal view video, my glottis is shown as a mostly symmetrical, bat-wing shaped black image in the center of the video. Before I take my breath, the glottis is mostly closed. When I take a breath, the glottis moves wide open. As I play the same note three times, each time doing a crescendo and diminuendo from piano to fortissimo and back down to piano, you can see the glottis slowly get larger, and then slowly get smaller again. While playing, I was consciously aware to keep my throat relaxed. While my glottis opened while playing loudly and closed while playing softly, I never felt like I had a “tight throat.” In this, Farkas’ radical idea that the glottis can have a role as a “whisper valve” in soft playing was verified. Fifty-five years after his idea was proposed, Farkas’ “most controversial stand”[20] has been verified as being accurate by the MRI Brass Repository Project.

Air attacks


Air attack exercise written by Edward Kleinhammer (1975)

The subject of air attacks is poorly understood. Air attacks were central to Edward Kleinhammer’s pedagogy, and he often wrote out an arpeggio exercise for students to work on – such as the image above, that he wrote for me during a lesson I had with him in 1975 – before finally codifying the exercise in Mastering the Trombone.[21] For him, the practice of air attacks to start notes helped to remove the tongue from the articulation equation, and develop better breath control. Some players use air attacks to start notes if they have a hesitation in articulation when they are under stress. They feel that taking the tongue away from the start of the note allows the note to speak without a stutter. I have rarely used air attacks to start notes at the beginning of phrases but I do use air attacks from time to time in the midst of phrases, especially in legato but also in articulated passages.

Over the years, I have suggested the use of air attacks to many students but most have difficulty understanding the concept beyond using an air attack to start a single note. But thanks to the MBRP, I can now show visually what I previously could only explain in words.

Video 7 – air attacks 1


[This video may be viewed on YouTube by clicking HERE.]

In this exercise, I play notes in two ways: first, a measure of notes is played with a traditional tongued attack. I chose the syllable TOH (as in “toe”) as opposed to TAH (as in “blah”) as a softly articulated syllable with which to start the tongued notes. Each tongued measure is followed by the same measure played with no tongue at all using the syllable HOH; I only used air to start each note. In the musical example above, tongued notes are indicated with a letter T and air attacks are indicated with a letter A.

As you view this video, you can see that when I used an air attack, the tongue was not engaged in articulation. The slight movement of the tongue that occurs during air attacks is caused by the pulsing of the air through the glottis and up the oropharynx. The tongue movement in air attacks is incidental, not causal. The size and shape of the oral cavity is essentially identical for both tongued and air attacked notes. The attack appears to be achieved by “huffing,” or pulsing the air with my diaphragm; whether the glottis is also involved in this cannot be seen in the angle of this video.

Video 8 – air attacks 2 – Finlandia – tongued/double tongued/air attack


[This video may be viewed on YouTube by clicking HERE.]

To show the difference between single tonguing, double tonguing and air attacks, I decided to record an exercise that uses a rhythm from a passage of music in which I use rapid air attacks, Jean Sibelius’ Finlandia. This piece requires the bass trombonist to articulate low E-flats at a rapid tempo in a loud dynamic. While I could not play low E-flats on the trombone I played in the MRI scanner, I compromised by playing Sibelius’ rhythm on both low B-flat and pedal B-flat.

The exercise I played is slightly different than the one printed above; I modified it when I was in the scanner to reflect Sibelius’ exact rhythm. You will hear me play two measures of each note tongued, then two measures double tongued, then two measures with air attacks.

As you will see, single tonguing resulted in a clear articulation. Double tonguing was not as clean as my single tonguing at this tempo and dynamic, and the air attacks come across like a machine gun rat-a-tat-tat. I have used this type of air attack when performing Finlandia, and with this video, a new visual tool is now available to help players understand how this kind of attack works.

These fundamental exercises and the resulting videos summarize a few of the important things I learned as a result of taking part in the MRI Brass Repository Project. But there were a few more esoteric phenomena related to trombone performance that I was able to explore in Göttingen. My friend, John Ericson, who is Associate Professor of Horn at Arizona State University, has long been curious about how the tongue performs while bending the pitch on a note. Trombone players don’t use the skill of bending pitch very often because we can correct pitch with our slide. But I do bend pitches when I play serpent and ophicleide, and sometimes when I play a trombone without an F-attachment and I need to play a note that is not on the instrument, such as a low E-flat or low-D.

Video 9 – pitch bends

[This video may be viewed on YouTube by clicking HERE.]

I decided to record an exercise where I would play several notes and bend them down to the lowest possible note before the note “broke” and then bend it back up to the original note. Lower notes would bend more easily than higher notes, owing to the flexibility of the embouchure in the low register.

Intuitively, I expected that as I bent a note lower, my tongue would flatten and move lower in my oral cavity, and as the note bent higher, my tongue would rise higher. But as you can see in the video above, the exact opposite occurred. Except for the pedal B-flat, which had the greatest bending ability because of lip flexibility in that extreme low register, my tongue raised up higher as I bent the pitch lower. This was a great surprise, especially since the feeling I had in my throat was that my tongue was moving lower. How to account for this? Because the pitch was being bent by the movement of my embouchure, perhaps the tongue rises to narrow the oral air channel to keep the note from breaking to the next lower partial. Clearly there is more study to do to understand this phenomenon. Still, this is a fascinating example of the value of the MBRP in  helping to understand something that in reality was at odds with how it felt.

Video 10 – whistling

[This video may be viewed on YouTube by clicking HERE.]

I also wanted to do an experiment in the MRI scanner related to whistling. Teachers often use whistling as a way to describe the movement of the tongue when we play notes in the upper register. With whistling, the embouchure does not, in the main, determine pitch. If you pucker your lips and whistle a low note and slowly glissando to your highest possible note, you will see that your lips move very little or none at all, and you have the feeling that your tongue is raising higher in your oral cavity as the pitch goes higher. I wanted to test this metaphor for brass playing in the MRI scanner and see if it was true. It was. Mostly.

As you can see in this video, the sound of the whistle is not only determined by the pucker of one’s lips. The tongue must be high in the oral cavity in order to modify the airflow to a point where the vibration of air past the lips can create the whistle. However, as the pitch of my whistle got higher, my tongue had no room to move higher; it had to move forward in order to further close the oral cavity.

As a result of these findings, the whistle is shown to be a less than ideal metaphor for the movement of the tongue through various registers in brass playing. In whistling, higher pitch is created, in part, by the tongue going forward; in brass playing, it is created, in part, by the tongue going higher. However, in MBRP studies with other subjects, it has been found that when a person engages in “hollow whistling” – making the sound of air speed rising and falling through relaxed and slightly open lips without making an actual whistling sound – the tongue does mimic the movements the tongue makes while playing. Actual whistling might intuitively seem to be a good model for explaining the use of the tongue in brass playing, but in fact, we would be better to use “hollow whistling” as a more accurate model.

Video 11 – bugle call (Reveille)

[This video may be viewed on YouTube by clicking HERE.]

Finally, I wanted to play some music and see how my oral cavity looked in real-life operation while playing the trombone. Constrained by only being able to play the overtone series, I chose to play the bugle call, Reveille, known to every young person who has been to summer camp and to the men and women of the American Armed Forces as the call to wake up each morning. In this performance, I used a combination of single and double tonguing. The position of my tongue is always clearly visible: going back and forth during single tonguing and then up and down while double tonguing.


Left to right: Jens Frahm (standing, rear), Eckart Altenmüller (standing, middle), Arun Joseph (seated, rear), Douglas Yeo (seated, front)

After my two hours in the MRI scanner – the time passed very quickly and I actually had no idea I had been in the scanner for so long – I emerged energized and excited to see what I had done. I sat with members of the MRI project team to gain some understanding of what had just happened. In the photo above, I am seated in front of a computer monitor that shows one of my videos. Eckart Altenmüller is seen looking over my left shoulder, holding a plastic model of the tongue, while Jens Frahm (standing) and Arun Joseph (seated) looked on. The resulting conversation opened my eyes to workings of my tongue and other organs in my oral cavity in a new way.  Also, our discussion revealed that in my videos, the tip of my tongue was not always imaged as clearly as it is with some other players when it moves to the most anterior (frontal) position. The reason for this is the fact that I have a titanium dental implant in one of my eye teeth that created what is called a susceptibility artifact that led to some signal intensity alterations at that place in my mouth. This is sometime seen as quick flashes of light that some may mistake for spit/saliva. This metal implant did not, however, affect the clarity of the imaging in any other part of my oral cavity, and ongoing study with other trombonists who do not have such a dental implant will result in additional video with greater clarity of the tongue in its most frontal position.


Left to right: Dirk Voit, Peter Iltis, Jens Frahm, Arun Joseph, Sonke Hellwig

Of course, a project like this needs a great deal of help to make it happen. The support staff at the Max Planck Institute was tremendously helpful in myriad ways. The photo above shows the five people who were involved with me during my time in the scanner. They gave me instructions and encouragement, ran the computers and equipment, ensured my safety, and sent me home with data and information that I am still processing. To (from left to right) Dirk Voit, Peter Iltis, Jens Frahm, Arun Joseph and Sonke Hellwig, I owe a great deal of thanks. They, along with Eckart Altenmüller, are helping to change our knowledge about brass playing and are giving concrete answers to long held questions. To YAMAHA Corporation (bell construction coordinated by Naoki Suzuki) and Kelly Mouthpieces (Jim Kelly), I once again express my thanks for providing us with the needed instruments and mouthpieces to conduct the trombone testing.

The MRI Brass Repository Project continues. In the coming months, more elite trombone players will be tested along with players who have experienced embouchure dystonia. While the project is of immeasurable help as we work to understand the why of the how of trombone playing, it is hoped that the project will also provide keys to unlock some of the mysteries of embouchure dystonia. In time, all of the videos from the study will be made available for study by educators and players so future researchers can add new insights to the work done inside the MRI scanner room at the Max Planck Institute for Biophysical Chemistry. We are in their debt.

© 2017 Douglas Yeo. All rights reserved.

Douglas Yeo ( and was bass trombonist of the Boston Symphony Orchestra from 1985-2012 and Professor of Trombone at Arizona State University from 2012-2016. He has given performances and held teaching residencies on five continents, and in 2014, he was the recipient of the International Trombone Association’s highest honor, the ITA Award. His newest book is The One Hundred: Essential Works for the Symphonic Bass Trombonist (Encore Music Publishers), and he is currently at work on books for Oxford University Press, Rowman and Littlefield, and University of Illinois Press. He lives in Arizona in the foothills of the Estrella Mountains.


[1] Harold W. Atkinson, “Tongue Positions of Vowel-Sounds,” The Modern Language Quarterly, Vol. 1, No. 1, July 1897, 13.

[2] Edward Kleinhammer, The Art of Trombone Playing. Evanston: Summy-Birchard Company, 1963, 63.

[3] Edward Kleinhammer and Douglas Yeo, Mastering the Trombone. Ithaca: Ensemble Publications, 2012 (Fourth Edition), 15.

[4] ed. Bruce Nelson, Also Sprach Arnold Jacobs: A Developmental Guide for Brass Wind Musicians. Mindelheim, Germany: Polymnia Press, 2006, 55.

[5] Arnold Jacobs, “Special Studies for the Tuba,” Hal Leonard Advanced Band Method (Basses/Tuba). Winona, Minnesota: Hal Leonard Music, 1963, 56.

[6] Philip Farkas, The Art of Brass Playing. Bloomington: Brass Publications, 1962, 62

[7] Harvey Phillips and William Winkle, The Art of Tuba and Euphonium. Secaucus: Summy-Birchard Inc., 1992, 34.

[8] Philip Farkas, The Art of Brass Playing, 47.

[9] Joseph (Jody) C. Hall used x-ray photographs of nine trumpet players as a basis for his his 1954 study of vowel sounds but he did not employ video. See: Joseph (Jody) C. Hall, A Radiographic, Spectrographic, and Photographic Study of Non-labial Physical Changes Which Occur in the Transition from Middle to Low and Middle to High Registers During Trumpet Performance (Ph.D. dissertation, Indiana University, 1954). In 1967, Joseph A. Meidt led a study of 10 brass players (five horn and five trumpet), in which the subjects performed several short musical excerpts while being filmed with a Rotalix x-ray (cineflourography) machine. However, the x-ray film showed the tongue only faintly and did not show the operation of the glottis and soft palate at all. See: Joseph A. Meidt, A Cineflorougraphic Investigation of Oral Adjustments for Various Aspects of Brass Instrument Performance (Ph.D. dissertation, University of Iowa, 1967). Also: Lyle C. Merriman and Joseph A. Meidt, “A Cineflourographic Investigation of Brass Instrument Performance.” Journal of Research in Music Education, Vol. 16, No. 1 (Spring, 1968), 31-38. Also: In 2013, C. Schumacher led a team that became the first to use real-time MRI video in a limited study of trumpet players. The MRI Brass Repository Project has expanded on that work by broadening their study to include horn and trombone players, employing the fastest MRI video film speeds ever published of up to 100 frames/second, and using both elite and embouchure dystonic subjects. See: M. Schumacher, et. al, “Motor Functions in Trumpet Playing: A Real-time MRI Analysis.” Neuroradiology, 2013; 55 (9), 1171-81.

[10] See, The project was originally titled the International MRI Horn Repository Project; its name was changed to MRI Brass Repository Project in 2017.

[11] From 1995-2016, Peter Iltis also taught horn at Gordon College until embouchure dystonia ended his playing career.

[12] Peter W. Iltis, et. al., “Real-time MRI comparisons of brass players: A methodological pilot study.” Human Movement Science, Vol. 42 (2015), 132-145. Peter W. Iltis, et. al., “High-speed real-time magnetic resonance imaging of fast tongue movements in elite horn players.” Quantative Imaging in Medicine and Surgery, 2015; 5 (3), 374-381. Peter W. Iltis, et. al., “Divergent oral cavity motor strategies between healthy elite and dystonic horn players.” Journal of Clinical Movement Disorders, 2015, 2:15. Peter W. Iltis, et. al., “Inefficencies in Motor Strategies of Horn Players with Embouchure Dystonia.” Medical Problems of Performing Artists, 2016. Peter W. Iltis, et. al., “Movement of the Glottis During Horn Performance: A Pilot Study.” Medical Problems of Performing Artists, Vol. 32, No. 1, March 2017, 33. Peter W. Iltis, “When Science Meets Brass.” The Instrumentalist, Vol. 72, No. 1, August 2017, 36-39.

[13] See: Sarah Willis, Sarah’s Music – Music and Science, ; Peter Iltis and Eli Epstein, MRI Horn Videos: Pedagogy Informed by Science, ; John Ericson, Horn Notes Video Podcast 12: MRI horn insights, part 1, with Peter Iltis,; John Ericson, Horn Notes Video Podcast 13: MRI horn insights, part 2, with Peter Iltis,; John Ericson, Horn Notes Video Podcast 14: MRI horn insights, part 3, with Peter Iltis,

[14] Edward Kleinhammer (1919-2013) was bass trombonist of the Chicago Symphony Orchestra from 1940-1985. See: Douglas Yeo, “Edward Kleinhammer: A Life and Legacy Remembered.” International Trombone Association Journal, Vol. 42, No. 2, April 2014, 24-31.

[15] Arnold Jacobs (1915-1998) was tubist with the Chicago Symphony Orchestra from 1944-1988.

[16] Brian Frederickson and John Taylor, Arnold Jacobs: Song and Wind. Gurnee, Illinois: WindSong Press, 1996, 93, 141-143.

[17] Philip Farkas (1914-1992) played horn in many American symphony orchestras including the Chicago Symphony (1936-1941; principal from 1947-1960), Boston Symphony and Cleveland Orchestra. He was Professor of Horn at Indiana University from 1960-1984.

[18] Philip Farkas, The Art of Brass Playing, 62.

[19] Peter W. Iltis, Sarah L. Gillespie, Jens Frahm, Dirk Voit, Arun Joseph, and Eckart Altenmüller, “Movement of the Glottis During Horn Performance: A Pilot Study.” Medical Problems of Performing Artists, Vol. 32, No. 1, March 2017.

[20] William Carter, “The Role of the Glottis in Brass Playing.” The Instrumentalist, Vol. 21, No 5, December 1966, 75.

[21] Edward Kleinhammer and Douglas Yeo. Mastering the Trombone, 14.