Similar to the method in which a woodwind player performs with an excess of pressure on the reed, the tuba and euphonium player can tighten the lips past a normal amount in order to create a restricted, “choked-off” sound. This technique is structurally very simple—the player simply tightens the lips more than normal and attempts to perform normally.
This technique is much easier and effective in the middle to high registers. This is due to the tightening effect of the technique, as lower range notes require a much looser embouchure in order to speak properly. It is still possible in the lower range, though, but may not be as effective.
The most vital piece of information to know about this technique is its potential to be damaging to the embouchure. When done moderately and with practice, this technique is perfectly acceptable to the prepared tubist/euphonist. If called for excessively and/or at a sustained high volume, this technique begins to veer into dangerous territory. As with many techniques, care must be taken not to overly tax the performer. Given the difficulty and somewhat extreme physicality of the technique, this is not a technique that all performers will be comfortable performing, and indeed it is not a particularly well-known technique.
This technique is seldom used, and as such, does not have a standard notation. Since the technique is often used on a spectrum (from ordinario embouchure to overpressured), it is helpful to notate this technique in a way that can be changed over time. One possibility involves the use of a rectangle above the main staff, which can be filled with a solid color in order to show full overpressurization, and then left hollow for ordinario embouchure. In the provided musical example, the overpressurization is activated at a constant rate, and as such is notated using a wavy line and text direction above the affected note.
Works to consider (bolded titles are particularly representative examples of this technique)
Tabula 51 – Kari Besharse