39. Creating Variations
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Figure 39.1 shows a Variation called NewTwenty, based on an existing Variation called
twenty, being set-up. A Variation in Kangas Sound Editor is what you can use
to allow the amplitude of individual frequencies in a Harmonic or anti-Harmonic to vary over time. For example,
there are real life musical instruments where the fundamental frequency out-lasts the harmonic frequencies;
a Variation would allow a decay, over time, of individual harmonic frequencies to be specified so that this
effect can be achieved. It would also allow mutating effects: for example, the tone of a note or sound changing over
A Harmonic or anti-Harmonic record can optionally refer to a Variation. If no Variation is referred to, the
amplitude of individual frequencies will be fixed throughout the lifetime of a sound relative to each other —
just specifying a Sound box Volume graph varies the amplitude of all the frequencies of a
Harmonic or anti-Harmonic simultaneously to the same extent.
Each row in the table corresponds to a frequency of a Harmonic or anti-Harmonic which refers to this
Variation. The ways that a Variation can effect the frequency of the Harmonic/anti-Harmonic follow:
If the Zero column flag is set then the amplitude of the corresponding frequency will
be zero throughout the duration of the sound, irrespective of other column settings.
The columns Overall offset, Overall duration, and Overall graph work together. Overall offset and Overall duration are in seconds, unless the Overall ofs %
and Overall duration % checkboxes are checked, in which case their values correspond to
percentages of the duration of the sound. For the period defined by Overall offset
(which starts from when the Sound period starts), the amplitude of the corresponding frequency will be zero. For
the period defined by Overall duration (which starts when the period defined by Overall offset finishes), the amplitude can be a fraction of, but not greater than,
its normal value (as determined by Sound box Volume graph and Vol. ext.).
The actual amplitude is set by the graph entered in the Overall field, provided that
the Overall graph checkbox is checked. Note that if Overall duration is 0 (zero) it is taken to be the entire
duration of the sound less Overall offset.
The columns Interval, Initial Interval (numeric field), Duration, Period graph, Interval graph, Duration graph and Initial Interval
(checkbox) work together. If the Initial Interval checkbox is checked then for the
period of time defined by Initial Interval (numeric field) the amplitude of the
corresponding frequency will be zero. The amplitude will then follow a repeating pattern, repeating every Interval seconds (unless Interval % is checked, in which
case it is a proportion of the duration of the sound). If the Interval graph checkbox
is checked, this interval will not be fixed; it will depend on the graph in the Interval field (which should yield y-values > 0) and will be a fraction of the value
in the Interval column. The duration of the period is determined in a similar way by
Duration (numeric column), Duration Graph (checkbox) and Duration (graph field); the Period graph is scaled over the
period set by the resulting duration, which could be greater than or less than the Interval value. The graph in the Period field (Choccie in figure 39.1) is effectively also the amplitude graph; in other words, it
determines the fraction of the normal value of a frequency over the (repeating) period. There are also a couple
of defaulting rules:
Although all this may sound a bit complicated, this is really just a way to have parts of a sound getting
quieter and louder and quieter and louder and so on throughout the duration of the sound.
- If the Duration column value is zero, it will be taken to be the same as Overall duration (see list item 2).
- If the Interval column value is zero, it will be taken to be the same as the
Duration column value.
Note that the functionality in the above two list items is not mutually exclusive; in other words, all column
values can be active simultaneously in any given row.
Regarding the Fill controls, the various flags' checkboxes can be checked or unchecked
en masse by first setting Fill target to Flags; then,
checking one or more of the checkboxes that correspond to columns (e.g., check OG for
setting or clearing checkboxes in the Overall graph column); next, setting a
Fill value of 1 (to check the target checkboxes) or
0 (to uncheck the target checkboxes); and finally proceeding to set a target range of
indices, a Fill mode and clicking on the Fill button. See page
36 for the basics of