Sempre più interessante, soprattutto l'ultimo capoverso nel quale spiega come mai le trombe convenzionali suonano intonate solo quando si allunga la pompa d'intonazione fino a portarle in La.
Flexibility and Stability
The two main variables in the pitch center with regard to the response of equipment are flexibility and stability. A stair-step diagram works well to illustrate how these qualities affect performance. Just as a certain size and distance between stairs will best suit someone of a specific stride and foot size, the response characteristics of the mouthpiece and instrument one uses should provide a pitch center that is consistent and comfortable for each individual player.
When changing registers using conventional mouthpieces, one can easily notice the shift in the subjective pitch center. If one does not adjust the body to compensate when playing octave C’s, the octaves will be compressed. The low C will be sharp, which is to say the subjective pitch center will be too high. The C in the staff will sound flat to the low C, and the high C will be even flatter than the C in the staff.
This is because the subjective pitch center becomes lower as one plays higher on open octaves. This shift in subjective pitch center is why players experience less endurance and a less resonant sound as they play higher-pitched instruments, and it is because of the difference in the way the subjective pitch center shifts in the various keys of trumpets that we make mouthpieces for each key of instrument. The same pattern of shifting pitch center also exists to varying degrees in horn, trombone, and tuba performance as well, with the most inconsistency found in the horn.
Using conventional mouthpieces, the subjective pitch center changes throughout the register. This diagram shows octave C’s.
Using Monette mouthpieces, the subjective pitch center stays the same throughout the register..
In the stair-step diagrams shown above, the vertical part of the stair step represents flexibility, which determines, among other things, how much a note can be bent “off center” before cracking up or down to the next overtone. It also determines the “distance” between notes one feels when playing intervals. The horizontal part of the stair step represents the stability, or how secure the equipment feels as one articulates—articulation meaning note connection, not just tonguing. Note: The stair-step graphs in this guide depicting pitch center show evenly spaced steps for the sake of simplicity. To be more accurate, the vertical part of each step should get shorter when ascending, since the “distance” (interval) between overtones decreases as one ascends in register.
It is interesting to note that if one uses a conventional mouthpiece on a Bb trumpet which has the tuning slide pulled out enough to lower the instrument to the key of A, the octaves will line-up almost perfectly. This demonstrates the impact of tradition in contemporary mouthpiece designs, given that many 19th-century trumpet and cornet players used instruments pitched in A.
