Section 1A: What is a split-tone?

A split-tone is a type of lip multiphonic achieved by splitting the embouchure between two adjacent partials, creating a dyad-based multiple sonority on a brass instrument. Lip multiphonics differ from voice multiphonics in that they are multiple sonority created entirely by the player's lips- as opposed to the more common voice multiphonics, which is a combination of singing and playing. This book focused primarily on split-tones as they are main technique utilized in the works that this writing focuses on.

Section 1B. Lip slur and over focus:

A split-tone is essentially achieved by reducing the resonance on an individual tone, but over focusing on the center of this pitch. One then takes this over centered note and bends it down slightly to find the point where the note breaks to go down one partial. Instead of going down to the lower tone, the trombonist holds the note at the break point, which results in a dyad-based sonority. However, the lower tone of the dyad sounds higher than it normally would given that the player is not bending to a point where it can resonate exactly. Over time the player essentially develops a feel for the center of the split-tone and it becomes something that s/he can go it into with an expectation of stable and predictable results.

In this text, split-tones have been refereed to as “dyad-based.” What is meant by this is that, since a split-tone is made by splitting between to adjacent partials in the overtone series, its primary pitch content is comprised of those two tones. However, given that split-tones are created by using interference patterns in the instrument [much like woodwind multiphonics], the result is a complex sonority that is only primarily based in those two tones .

The following exercises are intended to help introduce a player to the fundamentals of how to create a split-tone, associate them with standard playing modes, develop control in their use, and learn to manipulate them for a variety of practical uses.

The first exercise is to simply start on a comfortable and flexible note [middle F in the written exercise] and alternate between the traditional 'o' phenom and an exaggerated, overly centered 'e' phoneme. The purpose is to do nothing more than to get comfortable going between the two sonorities and really learning where is other sound is. Make sure to do this focus inside of the mouthpiece- try to avoid exaggerated physical changes outside the very center of one's embouchure. When focusing in onto the 'e' really strive to cut out as much of one's resonance as possible- create a highly focused tone with as little extra sonic information as possible. Then simply increase the speed of transition between the two, as this lays the fundamentals for quickly splitting a tone. Make sure to get all the way back to a full, healthy tone- no favors are done by training oneself to play regularly with a pinched embouchure.

The purpose of the next exercise is to associate each individual split tone with both the notes being split and the stable center of the note one is splitting from. Strive to make as exaggerated a difference as possible between the standard open 'o' in traditional brass playing and an overly centered 'e' phoneme. Use this over focused 'e' tone to pivot into the split tone. A slight pivot of the actual horn can help- some people will find pivoting down the most helpful, but sometimes a slight pivot up is what the tone needs. Don't be afraid to experiment with different motions to try and find the point where one's sound splits, but remember that the distance one needs to pivot is quite small.

It can also be useful to “keep it in the mouthpiece” by making the pivot with the lip instead of the horn, generally by rolling the lower lip out slightly. Bending from the lip draws one's attention to the center of the embouchure and can be a useful way of developing a clear mental connection with the over-focus concept. One may find that the most effective method is to simply experiment with both varieties of pivot processes to find the mental and physical over lap between them and the center that is most comfortable for the individual player.

Do not leave out the lip slurs, they can be an incredibly helpful way to keep the two pitches one is striving for in the ear. Like all brass playing- the better one can hear the sound, the better one will play it.

This exercise is written for the 3:2 split tone but it is a concept that can be applied as the basis for any expansion up the overtone series. 

Once a split tone can be reliably achieved the next major hurdle in finding stability. Associating one's split tones with lip slurs is a reliable way to improve the mental side of the technique by making them intrinsically tied into one of the most fundamentally stabilizing aspects of trombone playing. On the physical side, attempting to maintain a focused embouchure once the split tone has been achieved is invaluable. If one can focus in on maintaining the 'e' phoneme while playing a split tone, the performer can develop a habit of remaining in the center of the sound while the sound created is battling both the acoustics of the instrument and the traditional embouchure the trombonist has training into his/her natural functioning. Like any technique, new or old, the most effective way to solidify it is through consistent, focused, and considered practice.

Section 2: Lip Bend

Another way of finding split tones is by [carefully] destabilizing one's embouchure. The most effective way of doing this is to do slow, downward lip slurs paying careful attention to the breaking point where, to use the included example, the F breaks and falls down to the Bb. Repeat this a number of times, trying to memorize where the break is. Try to stop the slur at the breaking point, hold the tone there, and crescendo into the break. Often this exercise is most effective when done in the opposite manner to the 'over focus' ones- play it quite loudly, without the previous careful approach.

This controlled destabilization can further deviate from the previous exercises in the fact that it can be aided by external motion. Puffing the cheeks and allowing some air in between the lips and the teeth can help achieve the needed instability. This is a fairly strong deviation from the standard 'over-focus' approach to achieving split tones and [puffing the cheeks] should not be overly relied upon to achieve split tones. Puffing does have some very particular applications in aiding with extremely loud attacks, finding 2:1 split tones [which are covered in a later section], and preparations for circular breathing.

Another function of a puff based split tone is that it tends to produce a much more complex, extremely loud, noise based sound, as opposed to the more clear and controlled dyad based sound of a centered split tones. So while a properly centered split tone offers a sound with more reliable control and stability, the split achieved by the destabilization of the embouchure has its applications.

It can be helpful, similar to legato practice, to try and 'play into' the space between the notes. It is written as a crescendo in the exercises, but this can also be thought of as simply putting emphasis on the space in between. Another helpful trick can be to slur to the halfway pitch and then to the bottom pitch. Much like a lip slur helping guide one's ear, hearing a middle point can help guide a player to the breaking point of the slur.

Since this exercise involves loud destabilization of the embouchure it is recommended that the user be intelligently cautious with its application. Make sure to take time after to play a few simple lip slurs and long tones to make sure one's face is put back in order and an unintentional split tone doesn't make its way into other playing.