Nonmetrical onset timing with specified pitch

The scale used extends over two and a half octaves, including scale degrees below the lowest tonic pitch heard (see Extended scales). In the second system, however, space is saved by showing only the pitch range actually used in that system.

The introduction, which occupies the first system of our score, has no regular pulse or beat, so time here is measured by the clock, in seconds (see Pulseless onset timing). The clarinet begins with a trill - an alternation between two adjacent scale degrees - which (in this performance) starts slowly, accelerates, and then slows down somewhat. Then comes a fast upward scale that turns into a pitch slide, gradually levelling out towards the highest pitch (see Pitch bending).

A regular meter and tempo is established when the theme begins (see Beats, Bars). In the first two bars, the beat division changes from two pulses per beat to three and then back to two; as the tempo and the number of beats per bar stay the same, the changes of beat division are indicated with “/3” and “/2” only.

The theme includes many extra-scalar pitches, which no doubt have much to do with what Gershwin means by “blue.” Most onsets in the theme are articulated by tonguing, but some only by changes of pitch, as in the introduction (see Articulation and melisma).

In reality, there are bound to be some “gaps” in the sound, both for variety of articulation and for the player to take a breath. These gaps could easily have been indicated in the score by making some of the rotated T symbols shorter and leaving some space between them, but in this case it was decided to use an unbroken melody line to depict the continuity of the phrase and the way its long descent mirrors the long ascent of the introduction. As always, Global Notation offers a range of choices rather than an “algorithm” for converting sound into graphics, and leaves users free to decide what they want to specify.

We now have the means to notate rhythms and melodies with any desired degree of complexity and detail. Naturally, there are many musical situations we’ve yet to cover - not least, the simultaneous combination of different pitches in “harmony” and “counterpoint.” These are covered in more “advanced” sections of the website on pitch combinations. Meanwhile, there are a couple of other aspects of musical sound to consider, beginning with a very basic one: how loud are the sounds?