The fourth of bb is eb and has six flats (b, e, a, d, g and c):—
eb f gb ab bb cb d⊄ eb
1 2∼3 4 5∼6∪7∼8
The fourth of eb is ab and has seven flats (b, e, a, d, g, c and f):—
ab bb cb db eb fb g⊄ ab
1 2∼ 3 4 5∼6∪7∼ 8
The student should find the minor keys having more than seven flats.
The harmonic minor scale is awkward in formation on account of the augmented second step between steps six and seven. All augmented intervals sound harsh and are difficult to sing tunefully. For this reason, another form of minor scale is sometimes used which eliminates the augmented second step. This form is called melodic minor and is used, as its name implies, only for melodic purposes. It defies harmonization for the obvious reason that its ascending form differs from its descending form.
The melodic minor scale has the sixth as well as the seventh raised by accidental in ascending, but in descending, both the sixth and seventh are restored. The ascending form has whole steps between 1 and 2,—3 and 4,—4 and 5,—5 and 6,—6 and 7, and half steps between 2 and 3 and between 7 and 8. The descending form has its half steps between 6 and 5 and between 3 and 2. Notice that the descending form is as its signature dictates.
raised raised
Ascending: —1 2∼3 4 5 6 7∼ 8
Descending:—8 7 6∼5 4 3∼2 1
The ascending form of the melodic minor is nearly the same as the major scale, and for this reason it is best not to retain the raised sixth and seventh in descending. The subtonic in a descending scale does not lead (progress) to the tonic and therefore need not necessarily be situated one half step below the tonic.