Symmetric scales are those that have exactly the same sequence of intervals when played in ascending and descending form. In other words, we use the same logic (interval structure) to perform the scale in both directions: from bottom to top and from top to bottom.
The chromatic scale is an example of a symmetric scale, as its interval structure is: semitone – semitone – semitone – semitone, etc. Therefore, to execute it from the bottom to top or from the top to bottom we follow the same logic.
What are Asymmetric Scales?
Asymmetric scales are those that are not symmetrical. The major scale, for example, is asymmetric, as its formation sequence is not the same in the execution from the bottom to top compared to top to bottom. It is formed by the sequence: tone – tone – semitone – tone – tone – tone – semitone
Notice how this scale is seen from the bottom up: semitone – tone – tone – tone – semitone – tone – tone. That is, the interval sequence is not the same in both directions (bottom to top x top to bottom).
Most scales are asymmetric. This makes symmetric scales peculiar, with a sound (in most cases) which is easily distinguishable.
The application of each scale, however, needs to be studied separately.
Go to: Chromatic approach chord
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