NATURAL MINOR SCALE

Another way to divide the octave into seven parts is to use the same intervals of the major scale but lower the third, sixth, and seventh by one semitone. This produces the natural minor scale, also called the Aeolian mode. These three intervals, which distinguish it from the major scale, give it a more mysterious and melancholic character, especially the minor third and the minor sixth.

C MINOR SCALE

RELATIVE MINOR

The natural minor scale is also called the relative minor of the major scale. This is because, if I keep exactly the same notes of the major scale but take the sixth note as the root, I obtain a natural minor scale. For example, with the same notes of the C major scale, I take the note A as the root and build the A natural minor scale.

RELATIVE MAJOR

The reverse process also works: if we take the notes of the natural minor scale and start counting from the third, we get the major scale. In this case, we talk about the relative major.

A is the relative minor of C, and C is the relative major of A; both roots share the same set of notes and, when using these notes, both become strong centers of attraction.

For finding a natural minor scale we can simply take the major scale and start from the sixth degree. This approach avoids counting semitone by semitone and is more intuitive with practice.

C Major Scale (Relative Major of A)	Relative Minor of C (Relative Minor of C)	G Major Scale (Relative Major of E)	E Minor Scale (Relative Minor of G)
C	A	G	E
D	B	A	F#
E	C	B	G
F	D	C	A
G	E	D	B
A	F	E	C
B	G	F#	D
C	A	G	E

TRANSPOSITION

If we’re not yet confident with major scales, we can construct a minor scale from any root note by measuring the semitones between the degrees starting from the tonic.

	A MINOR SCALE	E MINOR SCALE	B MINOR SCALE
	A	E	B
+2 (SEMITONI)	B	F#	C#
+3	C	G	D
+5	D	A	E
+7	E	B	F#
+8	F	C	G
+10	G	D	A

Like the major scale, the seven parts dividing the octave are not equal. Between most notes there is a distance of two semitones, but between the second and third notes, and between the fifth and sixth notes, the step is smaller, measuring only one semitone.

DISTANCE BETWEEN NOTES

Another practical method to find the notes of the major scale is to calculate the distance in semitones between notes. Considering that not all distances are equal, we must learn this pattern, where T stands for tone (two semitones), the unit of measurement:

T = tone, S = semitone

T – S – T – T – S – T – T

RELATIVE VS. PARALLEL

All these tricks (counting semitones from tonic, or intervals between degrees) were especially effective for understanding the major scale. For the minor scale, we can now simplify: as mentioned earlier, we can just lower the 3rd, 6th, and 7th of a major scale to obtain the natural minor. The parallel minor scale is the minor scale that starts on the same note as a given major scale. For example:

• A minor is the relative minor of C major.

• C minor is the parallel minor of C major.

The parallel minor preserves the same tonic, offering deeper insight into the nature of minor intervals, because the gravitational center remains the same.

Still, knowing the relative major and minor helps in composition. Shifting the tonal center from major to relative minor (or vice versa) without changing the note set is a common technique used to add contrast without major changes.

SCIENTIFIC PERSPECTIVE

Just like in the major scale, what truly defines a scale is the ratio between the frequency of each note and the tonic.

For example, assuming C = 261.63 Hz, the harmonic ratios of the C natural minor scale can be expressed as:

Nome	Rapporto armonico	Frequenza (Do = 261,63 Hz)
Do (tonica)	1/1	261,63 Hz
Re	9/8	294,33 Hz
Mib	6/5	313,96 Hz
Fa	4/3	348,84 Hz
Sol	3/2	392,45 Hz
Lab	8/5	418,61 Hz
Sib	9/5 (16/9)	470,93 Hz
Do	2/1	523,26 Hz

However, some further considerations apply to the minor scale. Both major and minor scales are based on simple frequency ratios, which explains their strong tonal attraction. The minor scale, however, features more odd-numbered denominators, with the number 5 recurring often. Though these may seem like small details, they underlie the distinctive melancholic character of the minor scale.

SUBHARMONICS

The concept of subharmonics is not universally recognized as a physical phenomenon in the same way harmonics are, but it's worth noting that subharmonic series can produce pitch structures similar to a minor scale.

So even though this concept moves beyond pure physics, it offers interesting psychoacoustic perspectives: how our brain interprets sound might be just as crucial.

To borrow from an old philosophical question:

“If a tree falls in a forest and no one is there to hear it, does it make a sound?”