Phrase Arch

Music has a hierarchical structure, so that small units, such as melodical gestures, join to form subphrases, which join to form phrases etc. When musicians play, they mark the endnings of these tone groups.
This rule marks the phrase and subphrase endings by creating minute accelerandos and decelerandos within phrases and subphrases according to a parabolic function. Thus it increases the tempo in the beginnings and decreases it towards the endings.
The loudness is changed similarly creating crescendos and diminuendos.
The phrases and subphrases have been marked in the score file.

In this example two other rules are applied:

• Durational contrast, increasing or decreasing the duration contrasts between note values. In this example the last mentioned alternative have been selected.
• Punctuation, inserting micropauses after melodic gestures.

You can vary the effect of the Phrase Arch rule only.

Example: F Mendelsohn, Aria # 18 from "St. Paul", Op. 36.

No-Phrasing	k = 0	WAV file (2.5M, CD quality)	AU file (227k, good quality)
Medium	k = 1.5	WAV file (2.5M, CD quality)	AU file (226k, good quality)
Exaggerated	k = 2.5	WAV file (2.5M, CD quality)	AU file (225k, good quality)
Inverted	k = -1.5	WAV file (2.5M, CD quality)	AU file (223k, good quality)

The graph shows how much the durations of the tones are changed in % of their nominal duration.

No-Phrasing, k = 0
WAV file (2.5M, CD quality)	AU file (227k, good quality)

Medium, k = 1.5
WAV file (2.5M, CD quality)	AU file (226k, good quality)

Exaggerated, k = 2.5
WAV file (2.5M, CD quality)	AU file (225k, good quality)

Inverted, k = -1.5
WAV file (2.5M, CD quality)	AU file (223k, good quality)