Estudio reológico

Triadic generalization does not mean that only three notes are being used, just that these three notes are more important than the other diatonic and chromatic pitches. The same hierarchy of pitches dis-cussed in the previous chapter is relevant to this discussion. If a triadic melody is to include more than just the three triadic tones, some discussion of elaborating the basic three pitches is necessary.

There are many terms for auxiliary tones. Tones which elaborate the basic triadic tones are often called non-essential tones to distinguish them from the essential triadic tones. This is an unfortunate designa-tion as these tones are essential to the creadesigna-tion of an interesting melody. They are also known as auxil-iary tones or non-harmonic tones. In traditional music, some auxilauxil-iary tones may be labeled as ac-cented or unacac-cented depending on their rhythmic placement on or off the downbeat. In the polyrhythmic settings common to jazz, this distinction is unnecessary and may prove confusing.

Auxiliary tones embellish the basic triadic tones and will be revisited in following chapters as they apply to embellishing harmonically specific lines.

P

ASSING

T

ONES

Passing tones (PT) are the diatonic and chromatic steps between the essential tones. In a chord, passing tones are the diatonic notes between the chord members: C major triad = C (d) E (f) G (a b) C. In a scale, the chromatic tones between the adjacent scale steps may be chromatic passing tones. A chro-matic passing tone can be placed between adjacent diatonic tones a whole step apart. Any diatonic tone can have a chromatic leading tone. C

#

is the chromatic leading tone to D and the chromatic passing tone between C

n

_{and D. D}

b

is the chromatic passing tone between D

n

_{and C}

n

. The difference between C

#

and D

b

is the direction implied by the accidental. Chromatically altered tones tend to continue in the direction in which they have been altered. Flatted notes are lowered and therefore tend to resolve downward, sharped notes are raised and tend to resolve upward.. The chromatic scale is written two dif-ferent ways to indicate the direction of the accidentals. Sharps are used when ascending and flats when descending. Keep this principal in mind when writing music and the lines will be easier to read.

After identifying the primary triad pitches, a scale may be viewed as a triad with passing tones between the primary pitches and a chromatic scale may be viewed as a diatonic scale with chromatic passing tones.

& ˙ ^œ ˙ ^œ ˙ ^{œ œ} ˙

C

˙ # œ ˙ # œ ˙ ˙ ^{# œ} ˙ # œ ˙ # œ ˙ ˙ ˙ ˙ b œ ˙ b œ ˙ b œ ˙ ˙ b œ ˙ b œ ˙

Passing tones between Tonic (1) and Mediant (3) of a C major triad:

1 - 3 Diatonic PT Diatonic and Chromatic PTs

& ˙ ˙

Passing tones between Mediant (3) and Dominant (5) of a C major triad:

3 - 5 Diatonic PT Diatonic and Chromatic PTs

& ˙ ˙

Passing tones between Dominant (5) and Tonic (1) of a C major triad:

5 - 1 Diatonic PTs

Passing tones between Tonic (1) and Mediant (3) of a C Minor triad:

1 - 3 Diatonic PT Diatonic and Chromatic PTs

& ˙ b ˙

Passing tones between Mediant (3) and Dominant (5) of a C Minor triad:

3 - 5 Diatonic PT Diatonic and Chromatic PTs

& ˙ b ˙

Passing tones between Dominant (5) and Tonic (1) of a C Minor triad:

5 - 1 Diatonic PTs Diatonic PTs

Diatonic passing tones can be illustrated in this excerpt from a Charlie Parker line. The notes of the G triad are clearly delineated as they occur on the strong beats of the measure. The passing tones on the up beats move the line to the next chord tones.

4.1 Diatonic passing tones

& #

c j

œ œ œ œ œ œ œ œ œ

CT PT CT PT CT CT PT CT

œ œ

This excerpt from a Charlie Parker blues improvisation illustrates the combinations of diatonic and chromatic passing tones between adjacent chord tones. The G

n

is a diatonic passing tone between F and A, followed by the chromatic passing tone G

#

. The chromatic G

#

creates more pull to the chord tone A

n

. The G

#

is not heard as a minor third of F (A

b

), but as a raised pitch which wants to continue in the direc-tion in which it has been altered. The B

b

is a diatonic passing tone between A

n

and C. The addition of the B

n

reverses the tendency of the B

b

to point down as an upper neighbor tone to the A, and propels the line up to the C.

4.2 Chromatic passing tones

& b c œ œ œ # œ œ œ n

CT PT PT CT PT PT

J œ

CT

N

EIGHBOR

T

ONES

Tones on either side of a primary pitch are called neighbor tones (NT). The common practice in most music from the Baroque period to the present is to use the diatonic (from the scale or mode) upper neighbor tone (UNT) and the chromatic lower neighbor tone (LNT). In some situations, the LNT may be labeled a chromatic leading tone (LT). A diatonic instead of chromatic LNT may be found in some folk and ethnic music which is often due to chromatic limitations of the instruments and not musical prefer-ences.

It is easy to determine the LNT since it is chromatic. It will always be a half step below the tone to which it points. It should be written with a different letter name and with either a sharp or a natural sign. F

#

, not G

b

is the LNT to G

n

. A

#

, not B

b

, is the LNT to B

n

.

The UNT may be harder to determine and will change depending on the key signature, mode or scale. A simple C major triad (C-E-G) will have different UNTs depending on the key signature and context. A C major triad can be found as the tonic (I) in the key or C major, as the subdominant (IV) in the key of G major, and as the dominant (V) in the key of F major or F minor.

A C major triad will have the same UNTs and LNTs in the key of C major or F major.

If the C major triad is in the key of F minor, all of the diatonic UNTs are also chromatic.

C as V in F minor

The distinction is evident in Chopin’s choice of UNTs in this excerpt. The C7 chord is the dominant of F minor and yields the D

b

, F and A

b

as UNTs to the C, E and G. Note how the B

n

, a chromatic LT, points up to the C

n

. The use of a B

b

would have made the line want to move down to the A

b

. Listen to how the penultimate B

b

points down to and finally resolves to the A

b

. 4.3 Chopin: Nocturne in E

b

major, Op. 9, No. 2

A C minor triad can be found as the supertonic chord (ii) in B

b

major, the mediant (iii) in the key of A

b

major, and as the submediant (vi) of E

b

major or the tonic of C minor (i). Notice how the UNTs change according to the context. The UNT to the tonic is a whole step above when C minor is a ii, vi or i chord,

In document Comportamiento viscoelástico de dispersiones de grafeno y líquidos iónicos (página 47-65)