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"The type of triad on each degree of a minor scale is the same for every harmonic and melodic minor scale" in TCL grade 6 theory. What is meant by this?

I guess the types of chords are major, minor, augmented and diminished. How come the above statement is true? For example, we do not have augmented triads in natural minor scale.

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    @Aaron - that question essentially covers only major and natural minor scales, thus chords emanating from them. This is regarding harmonic and melodic scales so the chords we find from them will be different. And - TCL statement doesn't ring true!
    – Tim
    Nov 1 at 7:36
  • By grade 6 theory, what age/level do you mean? In the US, that might mean a 6th grader (age 11-12 years).
    – nuggethead
    Nov 1 at 22:58
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    Don't you have access to your teacher at Trinity College? Your question isn't really about music theory, it's about the specific (unclear) wording of your course materials. Nov 2 at 18:16
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The statement

The type of triad on each degree of a minor scale is the same for every harmonic and melodic minor scale

can be restated:

  • The type of triad on each degree of a harmonic minor scale is the same for every harmonic minor scale.
  • The type of triad on each degree of a melodic minor scale (ascending) is the same for every melodic minor scale (ascending).
  • The types of triads on each degree of harmonic minor scales are not necessarily the same as the types of triads on each degree of melodic minor (ascending) scales.

The reason for this is that each type of minor scale is defined by a unique series of intervals. The illustration below shows the interval sequence for each minor scale type and a table of the triads that can be formed within each scale type.

Natural minor

M2 m2 M2 M2 m2 M2 M2

Scale degrees Thirds Chord quality
1 3 5 m3 M3 minor
2 4 6 m3 m3 diminished
3 5 7 M3 m3 major
4 6 1 m3 M3 minor
5 7 2 m3 M3 minor
6 1 3 M3 m3 major
7 2 4 M3 m3 major

Harmonic minor

M2 m2 M2 M2 m2 A2 m2

Scale degrees Thirds Chord quality
1 3 5 m3 M3 minor
2 4 6 m3 m3 diminished
3 5 7 M3 M3 augmented
4 6 1 m3 M3 minor
5 7 2 M3 m3 major
6 1 3 M3 m3 major
7 2 4 m3 m3 diminished

Melodic minor (ascending)

M2 m2 M2 M2 M2 M2 m2

Scale degrees Thirds Chord quality
1 3 5 m3 M3 minor
2 4 6 m3 M3 minor
3 5 7 M3 M3 augmented
4 6 1 M3 m3 major
5 7 2 M3 m3 major
6 1 3 m3 m3 diminished
7 2 4 m3 m3 diminished

Related questions

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    This seems like a pretty trivial observation to be making in a grade 6 theory course, which makes me wonder if you have the correct interpretation, and if OP has relayed the quote accurately. If this is what they meant, it sure is a clumsy statement.
    – ex nihilo
    Nov 1 at 8:48
  • If that is really what the statement is supposed to mean, it's really convoluted. All it means is chord qualities stay the same when music is transposed. Nov 2 at 18:20
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As it stands, that statement is ambiguous. True, each triad made from the harmonic minor notes will be the same (for each key), and each triad made up from the melodic minor notes will be the same. (I mean - maj., min., dim., or aug.)It doesn't clearly state that, though. And then I guess we must involve the notes of the descending melodic (same as natural minor) as they will produce some different triads from the ascending melodic minor notes.

The statement needs a tidy up!

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The type of triad formed on a given degree of a harmonic minor or melodic minor scale is the same, irrespective of the key of the scale.

For example, the triad formed on the second degree of the D minor harmonic scale will be the same type of triad one would get by forming a triad on the second degree of, say, the E minor scale; i.e., both are diminished.

The natural minor scale, or aeolian mode, is identical to the descending version of the melodic minor scale. Therefore all of the triads found using notes from the natural minor scale can be formed using notes from the melodic minor scale.

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