Method
A widespread trend within contemporary wind music from the middle of the twentieth-century onwards is to decouple the acts of pressing different valves or keys and the resultant sound. This is achieved by notating the valves or keys to be pressed down at a given moment, potentially also with a desired rhythmic gesture. This will naturally result in a melodic gesture that is halting and unstable, given the technique’s bypassing of traditional fingerings.
Necessary information
When writing valve notation for the tuba and euphonium, there are a few potential pitfalls to avoid. First of all is the by now often repeated issue of the existence of multiple different kinds of tubas and (to a lesser extent) euphoniums. With the latter, one needs to be aware of whether an instrument is compensating or non-compensating, while the tuba contains no less than six different kinds of tuba to consider (BBb and Eb compensating, F, Eb, CC, and BBb non-compensating). There is also the issue of number of valves for the tuba; the standard for all of the non-compensating tubas is to have five valves, but even that isn’t a given.
It is highly recommended by the author that the composer either tailors their valve notation to a specific key and type of instrument, or allow for alternatives to be used by the performer in the case that they don’t perform an instrument of the proper type. See the musical example in the Rhythmicizing the instrument category for a demonstration.
Notation
The most common method for notating this type of effect is through the use of either a specialized staff (where each line represents a valve), or through a symbolic notation that visually represents the opening and closing of the valves. Either method is acceptable; consult the example for Rhythmicizing the Instrument for a demonstration. When using a separate stave for the technique, it is very important to remember that not all tubas contain the same number of valves. This may cause serious issues, unless the technique is limited to four valves; the author is unaware of any professional-level tuba or euphonium that has less than four valves, and limiting the technique to that number ensures that all tubas and euphoniums may perform the technique as written. Some alternatives may be found for works that require additional valves; the author has personally adapted a work originally written for the five-valve F tuba for the four-valve Eb tuba, even though the work relied extensively on valve notation involving five valves. In that case, the author simply added a “compensating” fingering by combining the fourth valve with one of the main circuit valves, approximating the effect in a suitable manner.
Relative Difficulty
Professional
Works to consider (bolded titles are particularly representative examples of this technique)
Hommage à Brian Ferneyhough – Claus-Steffen Mahnkopf
Tube space – Dmitri Kourliandski
The Composer's Guide to the Tuba 