harmonic theory I

scale

Most common music has one tonic , a tona center. It means that all tones are part of the tonic scale. A peace in C major uses from a tonal perspective only 7 tones of the c major scale. The C major scale has the tones: C D E F G A B* C. It suits to the white keys on a piano.

C-Major : C - D - E - F - G - A - B - C

The caracteristic feature of a scale is the distance between the tones. interval structure. the distances between 2 tones are called intervall. the intervals on each major scale are equal.

accords

Accords are created from the scale tones. A accord is build of each second tone from that scale. it is a row of thirds.
For example C-major is a triad build of the c-major scale:

      tone          C     D     E     F     G     A      B     C

      no.           1     2     3     4     5     6      7     1

      accord        C     -     E    -      G                         =  C-major



or as tetrad:

      accord        C     -     E     -      G     -      B            =  C maj7

On every scale ton arises due pile up thirds a new scale and a new cord. The socalled modi take their name from the church modes.

Basetone  modus    4-tetrad     accord     scale       intervall structure
--------  -----    --------     ------     -----       -----------------------------

     C     1       C-E-G-B       C maj7     ionic       1   9   3   4   5   6  #7   1

     D     2       D-F-A-c       D -7       dorian      1   9  b3   4   5   6   7   1

     E     3       E-G-B-d       E -7       phrygian    1  b9  b3   4   5  b6   7   1

     F     4       F-A-c-e       F maj7     lydian      1   9   3  #4   5   6  #7   1

     G     5       G-B-d-f       G 7        mixolydic   1   9   3   4   5   6   7   1

     A     6       A-c-e-g       A -7       aeolian     1   9  b3   4   5  b6   7   1

     B     7       B-d-f-a       B -7/b5    locrian     1  b9  b3   4  b5  b6   7   1

     C     1       so            C          ionic        so

It arises 7 new scales but only 4 different tetrades (-7/b5, -7, 7, maj7).

Accord notations are here decalared .

The 12 tones of the octave can be grouped as accrod-tones, optional-tones and alterated tones. For example the C maj7 accord in tonic of C major :

Tone                C     C#    D     D#    E     F     F#    G     G#    A     A#    B     C

Accord              C     -     -     -     E     -     -     G     -     -     -     B

Option              -     -     D     -     -     F     -     -     -     A     -     -

Alteration          -     C#    -     D#    -     -     F#    -     G#    -     A#    -

(Alterated tones equals the black keys on piano.)

cadence

Cadences are rows of accords. Most popular peaces use only some accords. Mostly they are a part of the quartcadence. In a quartcadence accords follow a quard step.
The full quartcadence of C major is:

Cmaj7 Fmaj7 B-7/b5 E-7 A-7 D-7 G7 Cmaj7
or in steps a 1 4 7 3 6 2 5 1 cadence

The plural of popular peaces contain the quartcadence. so its good to kwon about it.

Allso popular are: D-7 G7 ( 2 5 )
or the '6 2 5 1' cadence : A-7 D-7 G7 Cmaj7

A step out of the tonica gives following cadence:
D-7 G7 G-7 D-7