It would be legitimate to ask why traditional techniques have not included all those resources which instruments really have to offer. How is it that, until today, possibilities which have always existed, have been so long ignored? How is it that instrumental techniques have become fixed in a pattern which does not allow any results except those actually in conventional use? The complex issues behind these questions are such that straightforward, irrefutable answers cannot be given .1
It is an unfortunate myth which claims that extended techniques are only "effects" that are in no way related to traditional instrumental techniques. 2 In fact, extended techniques are exactly what the term implies; extensions of conventional techniques. Throughout history, players and their instruments have been forced to adjust to the times, or risk becoming obsolete. For example, composers, clarinetists and instrument makers have precipitated, often through collaboration, instrument design changes since the earliest clarinet was developed; the innovative composer, through his music, challenged the clarinetist, who consulted the instrument builder on ideas for mechanical improvements that would simplify the effort necessary to achieve the desired musical result. However, no design of the clarinet has ever solved all of the awkward technical problems for the player. The most obvious proof of this statement is found in the fact that clarinetists have traditionally developed new or "alternate" fingerings to facilitate more reliable and musical results (suggested, and sometimes demanded by composers, conductors etc.) in performance. This has occurred despite the general emphasis by clarinetists in performance practice today on homogeneity of sound between adjacent pitches and registers. The usage of alternate fingerings in performance practice throughout the history of the clarinet, but most especially since the early twentieth century when most clarinetists were playing instruments that had a greater number of easily manageable keys and thus more alternatives to choose from, demonstrates the existence of the concept of extended techniques, well before the middle of the twentieth century. 3
Unfortunately, the clarinet has evolved by exclusively empirical methods rather than by progressive theories. This, in addition to the musical requirements of past epochs, is another reason that has led both instrument-builders and clarinetists towards this single objective: what Bartolozzi has fittingly described as "the emission of single sounds of maximum timbric homogeneity throughout the range of the instrument." 4 Rather than exploit the inherent qualities of the instrument, the clarinetist has been most often satisfied with refining the technique necessary for the performance of music from past musical epochs. Thus, during the twentieth century, much technique has become rigidly standardized.
The desire of homogeneity of timbre in performance practice is especially baffling when one considers the unique characteristics of the clarinet, most obvious in comparisons with other woodwind instruments. It naturally possesses four registers of very different color, and of much greater contrast than any other wind instrument. The lowest register (chalumeau) tends to be dark, and becomes diffuse as volume is increased. The throat register sounds thin with potential for significant adjustments of timbre by the performer, while the clarion register is full-bodied and brighter as one approaches its highest pitches. The altissimo register is bright and becomes thinner as one ascends towards the highest pitch extremes of the instrument (Example #1).
Example #1 (click on register to hear mp3)
Because of the absence or weakness of clearly heard partials in this highest register, differences of dark and bright are not applicable; thick and thin are perhaps more accurate descriptions, and usually relate to the particular partial level that is involved. For example, a pitch played on the third partial of a particular harmonic series may sound thinner than the same pitch played on the fifth partial of another particular harmonic series (Example #2).
Example #2 (click on music to hear mp3)
Various reed styles or mouthpieces may push these qualities towards thicker or thinner extremes.
The effect of volume on timbre is most pronounced in the chalumeau register. In fact, the greatest contrast of timbre characteristics occurs in this register of fundamentals, when it is produced at a high volume level. At the other extreme, the most uniform timbre can be achieved in soft passages towards the top of the clarinet range, since there is a lesser presence of higher harmonics in this register and at this dynamic level. In between these outer extremes, it can be safely concluded that loud volume levels exaggerate the timbre characteristic of a certain pitch, while softer volume levels produce timbre matching at a middle point between dark and bright. Of course, the performer has a certain amount of control over timbre variables through embouchure or air pressure manipulation; increased embouchure pressure will produce stronger partials while less pressure results in the weaker presence of partials. However, this manipulation most always distorts pitch level. [The timbre characteristics that have been defined for individual pitches in this study are not the outcome of extensive or unusual embouchure manipulation.]
In a more general sense, it is known that the harmonic spectrum produced by any instrument constantly changes in performance with every pitch and dynamic nuance that is played. In fact, there are even moment to moment changes in the balance of harmonics in every single humanly produced sustained tone. 5 Other aspects of the sound that effect these changes include formants, phase, noise elements, presence of inharmonic partials, and transients (attacks). From all of the above information, it is clear that timbric homogeneity is an unlikely and unnatural eventuality for the clarinetist to achieve.