On the whole, the following exercises are based off of 3:2 split-tones [tones split from the 3rd partial down to the 2nd]. This is because they can often be a solid base when exploring various manipulations of the split-tone. 3:2 provide a reliable groundwork for two primary reasons.

First, given that the 3:2 split-tone is the lowest traditional split-tone, there is nowhere for the split to fall if pushed out of focus and lost when exploring these extensions. With higher split-tones, there is a solid chance of falling down partials, but with a 3:2 the only note a player could fall to is still part of the split-tone.


Second, the second and third partials tend to be quite stable while also maintaining a very reliable malleability. Which is to say that the notes of those partials require a lower level of physical intensity to center and maintain, which allow the player more leeway when manipulating his/her playing in the following exercises. This is ideal because it allows the player modify his/her embouchure as needed without causing superfluous tension in the process. Ideally these exercises can be done in a way that is comfortable and does not have a negative effect on the day's playing work.


In this section, it may feel like the exercises have jumped from step 1 to step 50, given that the drills go from the fundamentals of production to fair advanced manipulations. Steps 2-49 are just simply dedicated work on the basics of producing split-tones and a consistent and comfortable relationship which their production. There is no special trick that separates a basic split-tone from these advance manipulations- like all work on the trombone it is just a question of diligent practice and patience with the time one's body needs to develop a skill.

Section 1: Circular breathing


Circular breathing split-tones is an essential element in both the works that are the focal point of these exercises. Given that the technique has, relatively speaking, a common use and an availability of quality instructional resources already existing; this text will not cover the basics of how to circular breathe. Instead it is written with the understanding that the reader already has this skill in his/her toolkit.


Relatively speaking, circular breathing split-tones is a fairly simple combination of techniques if the player already has a strong relationship with both individually. Circular breathing a split-tone does not require any form of significant alteration to either technique. The primary challenge is to maintain the focus of the split-tone embouchure while changing the tension in one's cheeks [i.e. puffing out and flattening them]. Once the trombonist can maintain a stable split-tone while puffing out and flattering his/her cheeks the inclusion of circular breathing is essentially the same as with standard playing. Therefore, in the following circular breathing exercise focus entirely on changing cheek tension.


In this exercise 'F' stands for 'flat' [one's normal playing position]. The 'P' stands for 'puff' [holding air in the cheeks in preparation for circular breathing]. The primary challenge, and focus, for this operation is to maintain stability inside the mouthpiece while the outside portion of one's embouchure is shifting dramatically. Focus in towards the center of the embouchure and try to keep it resilient and centered while doing one's best to avoid any more tension than is necessary to produce a stable sound.



Once the player feels comfortable maintaining a split while altering his/her cheeks, simply begin to add small breaths where useful in the above exercise. It's recommended that quick, frequent breaths be relied upon as opposed to a slower, more relaxed style of breathing. The less time one has with his/her split-tone being supported by the cheek muscles, the more stable and predictable it will remain.


Losing the center, and therefore the split-tone, is the primary pitfall of circular breathing with this technique. If one can maintain a focused center on the multi-phonic without developing undue tension, then circular breathing split-tones is relatively simple.




Section 2: Articulations


Another integral modification of the split-tone that both of the works hinge on is being able to double and triple tongue while executing split-tones1. Similarly to circular breathing, it is a technique that finds its primary difficulty in locating a method to implement one technique without interfering with the other.

Split-tones require a great deal of air, so the need for efficiency of tongue placement and use is paramount. Given the volume of air moved while executing a potentially unstable technique, it is incredibly important to keep the tongue as low as possible and articulate with as much economy of motion as possible. Considering the delicate balance that needs to be found, it can be helpful to approach this technique from the same standpoint one would when first learning multiple articulations. It's advisable to simply take one's time. Try to develop each tongue stroke on it's own and experiment to find the best balance and tongue position that works efficiently for the individual. Additionally, it is helpful to keep the notes long- think tenuto on every split-tone one articulates. They rely on air and vibration to maintain their focus, so it's essential to give each note as much of those things as possible.


For the 'T' or 'D' stroke, the physical use is virtually [if not actually] identical to a normal articulation, but the trick is to approach it much like legato tonguing at first. Start by articulating too little and focus on not damaging the stability of the split-tone. Just get comfortable with moving one's tongue while not stopping the simultaneous technique. As one's comfort level grows, slowly increase the amount of articulation until a clear 'T' or 'D' can be consistently produced.


The 'K' or 'G' stroke is slightly more complicated, but only because of position. It can be helpful to aim one's backstroke slightly higher than in normal playing. It is recommended to take the same approach as developing the front stroke to help spread comfortability to the backstroke. Take it slowly and deliberately add articulation without compromising the split-tone. Focus on maintaining a centered sound that a small, efficient motion does not disrupt.

The simple example below is a way to work on reliable attacks:



It is the same as any basic double tonguing exercise that is intended to focus on a reliable attack and uniformity between the two strokes. The backstroke part of the exercise begins with a 'T' articulation simply to help establish a clear split-tone. The reason for including such a common exercise concept is to help make a connection between normal double tonguing and double tonguing a split-tone. One should approach the technique in the same way one approached double tonguing when it was first added to his/her toolkit. Take it slow and keep it simple and it will find stability.

1It is recommended, for triple tonguing, to use a TKT KTK approach [essentially double tonguing] to help maintain an efficient split-tone center. Often a rapid, repetitive stroke [TTK] can lead to a larger interruption of air and a break in the split-tone. 

This second exercise falls within the same domain as the first.

 

The approach is the same as when double tonguing a normal tone. Strive to match both strokes in both sound and stability. It can be helpful to slightly accent the backstroke to match the clarity of the front stroke. Much like in normal double tonguing, look to avoid the pitfall of relying too strongly on the articulation and not letting the meat of the note sound. If one articulates too hard and reduces the vibration of the lips, the split will break. As one begins to combine the front and back stroke, work to maintain efficiency and note length to keep a full and healthy sound. The fullness of sound and length of note is essential to maintaining a split-tone while rapidly articulating.


Once a basic and comfortable relationship has been established with this approach, one can begin to simply apply it to his/her basic double and triple tonguing routine. It is recommended to apply one's routine to a consist overtone set. That is to say focus on consecutive 3:2 split-tones and then focus on 4:3 split-tones and so on. This is given to the fact that the different partials of split-tones frequently have different blows to them, so dividing by partial can help solidify each type. The below is example is one possible approach and is a useful exercise to assist in approaching Clint McCallum's Bowel Resection. Given that his piece is a essentially a long glissando, it is a practical way to focus on each individual slide position and search for consistent stability on each one.


Like preceding exercises, this one starts and ends with a slur to outline the split-tone and help enforce a relaxed and supple approach. Also, like previous exercises, strive for a focus and relaxed core to the splits- try to stay in the middle of one's playing and end the exercise as calmly as possible. Breathe as often as is necessary and play at a relaxed dynamic.

 

Continue this exercise by sequencing down by position.


Another precarious use of this technique appears in Nicholas Deyoe's facesplitter. The particular challenge is that one must start split-tones with rapid articulations, as opposed to articulating one that is already sounding1. This presents a dangerous situation because often the least stable moment of a split-tone is the initial attack. To accurately execute this technique one needs to be able to achieve a maximum amount of vibration on the very front of the articulation. One approach for this concept is to repeat a single split-tone multiple times. Begin by sustaining it and slowly shorten the sustain. Once on is able to still achieve an acceptable staccato split-tone, begin to add second note on the tongue's backstroke. As this method stabilizes one can slowly lengthen the articulated line. An example of this approach is below:

1Examples found in bars: 18, 21 ,28, 30, 51-53, and 76


Practice this exercise very deliberately, with a metronome, taking care to breath exactly in time and have rhythmic releases. Use the rhythm as momentum to create the sensation of playing on a line rather than a cold start. Start at a comfortable tempo, but quick enough to have a clear feeling of momentum. Try to keep each split-tone equal in resonance regardless of the length of sustain. It can be helpful to play this exercise at an assertive dynamic level with a feeling of forward momentum.

With all of these articulation concepts it is important to focus on staying in the center on the trombone seesaw. One must find a balance between an aggressively assertive attack while simultaneously maintaining a centered and calm control. One should not play at such a forceful volume as to force his/her embouchure open and lose the split. However, it is important to throw caution to the wind to a certain degree as being too conservative in one's approach can lead to tension and a reduction in vibration. Experiment to find a balance that is correct for the individual and allows maximum results with the least strain possible.


Section 3: 2:1 split tones


A unique timbre can be achieved by splitting between the 2nd and 1st partial. Given the width of the interval [an octave] and the low frequency involved, the 2:1 split-tone has a rather singular sound in which the interference pattern tends to be more prominent than the pitches being played. The process involved in producing a 2:1 split-tone is derived from the basic split-tone approach with some slight modifications.


The primary challenge is presented by the fact that the two partials being split require fairly divergent production methods and the player must find a way to balance the demands of these partials in order to create a stable multiphonic.


To start, it is effective to slur between the two partials and try to find the center, like in the previous 'Lip Bend' exercises of section 2. Once one feels comfortable with the breaking point between the two partials, an effective method is to imagine creating a physical split between the two divisions [the 1st and 2nd partial]. Do this by trying to keep the very center of the embouchure intensely focused, like with other split-tones. While maintaining this focus, attempt to bend from the 2nd partial down to the 1st partial, allowing everything but the center of the embouchure to relax into a comfortable pedal tone position. It can also be helpful to let the lower jaw come forward and make a slightly more exaggerated 'O' phoneme. The further one can move the corners of one's embouchure toward the pedal range while maintaining a focused center, the better chance one has of finding reliability. The 2:1 split-tone can often be found at the point where the 1st partial begins to intermittently sound and interfere with the 2nd partial.


Another challenge in this process is managing one's air stream. The predicament is to find a balance point of blowing slow, steady air, while maintaining a focused column that can blow through the middle of the embouchure and help maintain one's position at the breaking point between the two partials. There is no exact method to balance this other than conscious experimentation.


The exercise below is designed to focus in on the above steps in a simple way. One starts by playing a simple slur between the 2nd and 1st partial to help outline the involved pitches. Then one slowly bends down and up the octave to try and find the middle point where the lower tone just begins to start speaking, but the center can be maintained on the 2nd partial tone. Try and memorize the jaw position at this mid point. It is one of the most challenging parts of this techniques because it can often feel like one's jaw has no reference point and is floating in space. It is a bit like 5th position- there is not a great reference point, but consideration of one's body and taking the time to regularly check in lead to consistent results.

 

For some players, the 2:1 split-tone may come very quickly, but for the most part it is a fairly mailable sound produced by a loose embouchure so it can often take some time to consistently locate and call upon. A careful balance of patience, perseverance, and experimentation is important when working on this sound.



Section 4: common tones, valve transitions, and valve trills


While often utilized for their aggressive timbre and intense volume, split-tones are a dyad-based multiphonic and as such can also be used very effectively to create ideas of harmonic movement and chord progressions. One of the simplest ways to achieve this is by connecting multiple split-tones via common-tones. The except below is one possibility to demonstrate the concept. 





The numbers above the staff indicate the partials split and the numbers below the staff indicate slide positions [v indicates tenor-bass valve position].

By connecting successive split-tones by way of a common upper tone, one can maintain a stable drone while generating a motion beneath it. Given the utonal construction of the trombone [4:3 based pitch relationship between the open horn and the tenor-bass valve], the common-tones appear in order [3, 4, 5 in the example] and there for tend exist in simple harmonic relationships. Accordingly, this results in simple scalar movement of the lower pitch of the split-tone, allowing one to create subtle changes to a complex timbre.


In Bowel Resection, this technique had the practical application of allowing a smooth transition between a 3:2 and 4:3 [and back] split-tone, which allows for a more consistent level of volume. This application is covered more thoroughly in the Bowel Resection entry.


Another use of this concept is to use the valve and simple relationships to create harmonic shifts and chord progressions. By utilizing the tenor-bass valve one can switch between various overtone relationships without having a large shift in pitch, therefore being able to apply basic voice leading concepts to a solo melody instrument. One possibility is below.



The numerals above the staff indicate chord numbers and the numbers below the staff indicate slide positions [v indicates tenor-bass valve position].

This concept can allow a player to outline chord progressions in his/her playing and also provides a useful practice method for consistency of sound.

Creating chord progressions with split-tones is a underutilized method that is effective on the trombone, but is significantly more effective on large bore valve instruments [such as the euphonium and tuba] given the ease of legato and conical timbre. These instruments are intensely capable of creating harmonic motions similar to those possible with bass clarinet or bari-sax multiphonics.


Creating a consistent timbre of split-tone across different overtone relations is difficult to achieve but can be highly effective in works like Iannis Xenakis's Keren. While the passage is effective without timbrel consistency, the ability to make an even line with consistent color and attack is a practical tool to have to allow for musical flexibility.


In practicing simple relations and common-tones, like the above examples, one can find a simple and concise method for finding the balance of needed for a consistent result that comes from the demands of inconsistent production. That is to say that, much like getting an even sound across disparate registers, one must use unequal effort to create an equal sound. Approaching this issue through simple relations in a comfortable register is a good starting place for approaching this delicate issue.


Another functional exploitation of common-tones and the tenor-bass valve is for their use in split-tone valve trills. The concept is to simply execute a valve trill while maintaining a split-tone. Given what is involved in functionally executing the concept, the highest success rate lends itself to valve trills that are executed between two common-tones. The below exercise focuses in on one of the more uncomplicated valve trills to execute.



It can be useful to start on the high of the two split-tones [4:3] so that one's embouchure is starting from a place of higher focus. This way one can focus in on the diad with a higher tension and use that as a home base to help maintain a focused center. Like a standard valve trill, the challenge is to focus on blowing through the valve shift to maintain an even sound and help compensate for the difference in demands on one's air flow. It can be helpful to focus in on the lower notes, given that they are the moving pitches, while executing a valve trill to help instill stability.


Below are excerpts from Clint McCallum's gnarphwhallanie [for soprano, clarinet/bass clarinet, trombone, cello, and piano] that utilize valve trills. The first excerpt requires slide motion, which makes it decidedly more difficult than the second section, which is a pure valve trill.