I. Intervals

II. Scale Degrees

III. Scales and Keys

IV. Modes

V. Intro to Modulations

VI. Modulations of Aeolian and Ionian

VII. Other Modulations and Ethnic Scales

VIII. 5, 6, 7, 8, 9, 10, and 12 Tone Scales

Part VI: Common Modulations of Aeolian and Ionian

If you have studied music in the past, you will definitely know of two very common forms of Aeolian (natural minor): Harmonic minor and melodic minor. I will only introduce their construction in this lesson. It will not until later lessons that their full function will be understood.

Recall that natural minor is simply the minor scale: A B C D E F G A, without any modulations or changes at all. The two modulations of harmonic minor occur when a scale degree is altered.

Harmonic minor is a modulation of the minor scale which occurs when the 7^th degree of the scale is raised a half step. It adds what is called a harmonic, or tone whose interval is 1½, or a minor third. It is that sound that gives harmonic minor that beautiful Middle Eastern feel to it.

Like the Ionian system, the harmonic minor system has modes as well. And again, like major, each mode has a different tonal quality and sound to it that makes it unique. Note that in the classification of the modes of harmonic minor you should know that the names given vary from place to place and the names without parenthesis are the ones I learned. The ones in parenthesis are other alternative names I’ve learned and memorized from elsewhere (the ones in parenthesis are just a few on many names used to refer to them). To be totally sure, it’s probably best if you just refer to them as “Modes One through Seven of Harmonic Minor”.  

In addition you should be aware of the new tone that will be introduces. In all of major, it was composed of only 1 and 2, half step and whole step respectively. Harmonic minor has something special; it has a minor third or one and one half step. This is simply represented by a 3.

The routine is the same as always. The modes are classified based on the circle of fifths/fourths. With all the information we know, we can compile the list of modes and step differences:

Melodic Minor – The second common modulation of minor, this is found quite often in the Western music system. In this case, you raise both the sixth and the seventh scale degrees of the scale. This creates an unusual effect where the pentachord is minor and the tetrachord is major. On the way down however, the raised degrees are flatted back to their natural states, thereby turning the descending scale in the natural minor scale. In classical music theory you always play the natural minor scale on the way down. This is not always followed in contemporary music.

An Ionian Modulation:

It’s quite possible you’ve never heard of the Ionian modulations. Well they are very uncommon in the Western music system. In Jazz however and in ethnic music, these scales may be used quite often.

Harmonic Major – This scale I feel is one quite interesting. It’s composed of half major and half harmonic (as the name implies). However, I do not always like using this scale because I feel the “harmonic” Middle Eastern type of sound to the scale actually works better with a dark mode like minor. Major is too “upbeat” to go with a harmonic. It’s almost misleading because you expect it (especially noticeable on the way down) to have a dark tone to compliment the harmonic but it suddenly changes mood. This scale is derived by modulating the Ionian scale. Simply flat the 6^th degree. Note that this is NOT the same as the third mode of harmonic minor where you SHARP the fifth. The minor third occurs on the other side.

Mode to step difference comparison:

The four scale systems above, the Ionian System (Major), The Aeolian System (Minor), the Harmonic Minor System (Minor Modulation), and the Melodic Minor System (Minor Modulation) are the only ones commonly used in classical Western theory. While the Harmonic Major System (Ionian Modulation) is very uncommon outside of jazz, I felt it was important to put here as a comparison to the other related systems.