...search in soundme:

The harmonic development of a scale is given by the succession of sounds according to a certain type of interval. This is also valid for the diminished scales. You might have noticed that scales is plural. This is because there are many possibilities of interval structures inherent to the diminished scales. For example, the tone semi-tone scale or the semi-tone tone scale, where the relative arpeggios must be added. The first step consists of learning these ideas, and verifying the interval sequences of the diminished scales.

Tone semi-tone diminished scale

The tone semi-tone diminished scale is a succession to intervals made by separating every degree of the scale by alternating tones and semi-tones. Starting with the first degree we climb to the next degree (the second), which are seperated by one tone, then to the next degree (third), which are seperated by a semi-tone, and so on. When talking about the diminished scale, normally we intend the tone semi-tone succession.
Pay attention to one detail. Within an octave, there will be the name of one note that appears twice. This normally happens in every scale, since we have the doubling of the fundamental, something that also happens in the diminished scale. The difference is in the fact that there will be another note that appears twice, once natural and once sharp. In the example below we see the F and the F#. The rule of harmonic construction of the scales says that every note must have a different name, something that isn't possible within the diminished scale.

Semi-tone - tone diminished scales

Applying the same system to an alternate succession of semi-tones and tones, we can build the semi-tone tone diminished scale. Also in this case the interval includes the name of a note played twice, which in this example is Eb and E.

Diminished arpeggio

An arpeggio is built by harmonizing a scale by third intervals. In the diminished scale we can create a succession of sounds for the third intervals that will always have an interval of one tone and a half, either starting from the first degree of the tone semi-tone scale, or the first degree of the semi-tone tone scale. Either way we get a diminished arpeggio.

Properties of the diminished scales

The diminished scales (and relative arpeggios) have one common characteristic, which is the fact that the succession of notes at regular intervals riunites the scales into similar groups.
We have seen in the example above that the tone semi-tone diminished scale in C develops a series of tone and semi-tones at constant intervals. If you instead start with the Eb note, you get the same succession of tones and semi-tones, and the notes that make up the new diminished scale of Eb are the same as the previous tone semi-tone diminished scale in C. This means that we can obtain four tone semi-tone diminished scales within each diminished scale, with 1 1/2 tone intervals between eachother. Look at the example below.

All four scales (C, Eb, F# and A), are composed of the same identical notes. Therefore if you play one of these scales, in reality you are also playing the remaining three scales. With this system we can obtain a total of three groups of tone semi-tone diminished scales:

The same rules apply for the semi-tone tone diminished scales and for diminished arpeggios.
As you can see, when playing a diminished arpeggio in C in reality you are also playing that of Eb, F# and A. These rules may be a bit particular, but with practice using the diminished scales you will realize their enormous utility and the interesting sounds that these scales are able to produce.