Figure 5.1 shows what happens when the Sound box that contains the Harmonic box whose properties were just updated is selected: the bottom left of the screen now shows the properties for the selected Sound box. Graphs can be input for determining what happens to the volume and pitch over the duration of the sound. The duration of the sound can be a fixed value, such as 2 seconds, or it can be proportional to the current volume. The idea of making the duration proportional to the volume is a little like the difference between hitting a note on a piano lightly, or heavily when the note is likely to last for longer. Under the proportional-to-volume mode (Prop. to vol.), the value in the Duration edit field is used as a factor rather than an absolute time.
The Volume graph from zero checkbox, which is checked by default, means that the volume graph starts at zero and rises to a maximum of current volume plus volume extent (Vol. ext. field). Current volume is determined from the initial volume as set on the containing Sequence box property, and adjustments to volume as set on Interval and Repetition Group properties. If this box is unchecked it means that the volume starts off at the current volume, and can deviate from this current volume by a maximum of volume extent. Pitch changes are always dealt with in this way; in other words, using fluctuations from the current pitch.
The Pitch calc freq field is used to set the pitch calculation frequency to a value less than the general calculation frequency (which is a configuration parameter). Experimenting with this parameter can produce some interesting effects.
The Scale-to-fit checkboxes indicate whether the corresponding graphs should be stretched or shrunk to the duration of the sound, or whether they should be used without stretching or shrinking. In the latter case a graph that has an x-axis limit of, say, 2 would last for exactly 2 seconds; if the duration of the sound were less than 2 seconds, not all the graph would be used; if the duration were greater than 2 seconds, the graph would cease to have an effect after the 2 seconds was up.
The Invert checkboxes invert the corresponding graphs about the y-axis, so for a graph that normally rises from left to right, ticking inverted would make it fall from left to right, and vice versa.