Harmony for guitar

INTERVALS

Hi everyone! It is a great pleasure to be part of the collaborator team of the Guitar Clinic. I hope this column contributes sufficiently in the briefing of doubts related to this subject. The subject this month is one of the beddings of the musical theory - the intervals. Although such topic has already been explained in many music books and guitar methods, I concluded that it would be interesting to deal with the subject in a deeper way, As it was mentioned previously, this is one of the foundations of the harmony, both traditional, functional or jazzistical. Undoubtly, it’s very important for the musician to know and to understand all the intervals between notes, so that he can establish clear relations between its distances making possible a better visualization of structures of chords and scales. The following table shows a standard view for the intervals, displayed in two octaves:

Up to 7M, we have simple intervals. From 8J, the intervals are called composed. To know which is the composed correspondent of a simple interval, just add 7. To discover the simple correspondent of a composed interval, just subtract 7, as in the examples below:

2M (simple interval) + 7 = 9M (composed interval)

10M (composed interval) - 7 = 3M (simple interval)

 

The intervals can also be harmonic or melodic. The “harmonic” term means sounds played simultaneously, whereas “melodic” term means notes played in a successive way, as in the example above.

INVERSION OF INTERVALS

 

Ascending intervals are different of descending intervals. For example, 4J ascending of C is the note F, whereas 4J descending of C corresponds to the note G. However, it is possible to establish a logical relation between the intervals, as in the example below:

 

Ascendant Fourth = descendant fifth

Ascendant Fifth = descendant fourth

Ascending third = descendant Sixth

Ascendant Sixth = descending third

Ascendant Second = descendant seventh

Ascendant Seventh = descendant second

 

The addition of the two numbers must  be always equal to 9. In its inversion, all major intervals become minor, and vice versa, and all augmented interval becomes diminished and vice versa, and all perfect interval just  remains, as in the examples below:

 

Ascending 2m = descending 7M

Ascending 2M = descending 7m

Ascending 3m = descending 6M

Ascending 3M = descending 6m

Ascending 4J = descending 5J

Ascendant 4+ = descending 5º

Ascending 5J = descending 4J

 

CONSONANCE AND DISSONANCE

 

We consider harmonic consonances: 3m, 3M, 5J, 6m, 6M and 8J. 5J and 8J are considered perfect consonances, while thirds and sixth are considered imperfect consonaces. We consider harmonic dissonances: 2m, 2M, 7m, 7M and all the diminished and augmented intervals. In two voices, 4J is always  considered dissonance. In The three or more voices, 4J is considered dissonance only when it is formed with the bass of the chord. We consider melodic consonances: 2m, 2M, 3m, 3M, 4J, 5J, 6m and 6M.We consider melodic dissonances: 7m and 7M, and all the augmented and diminished intervals. In all the cases, the dissonance idea is sufficiently relative, depending mainly on aesthetic questions. What was considered dissonance in the classical period of erudite music could not be considered the same in jazz repertoire.

EXERCISES

 

1) Visualization and memorization: The exercises that follow  can  be somehow played in the instrument as they can be sung. Try to understand why some intervals are not mentioned because it would be redundant to make it when we practice ascendant fifths, for example, automatically we will be practicing  descendant fourths.

Ascending seconds: C, D, E, F, G, A, B, C.

Descending seconds: C, B, A, G, F, E, D, C.

Ascending thirds: C, E, G, B, D, F, A, C.

Descending thirds: C, A, F, D, B, G, E, C.

Ascending fifths: C, G, D, A, E, B, F, C.

Descending fifths: C, F, B, E, A, D, G, C.

 

2) Try to analyze the intervals of the chords and licks that you already play, trying to establish relations between the intervals and the shape formed in the instrument´s neck, classifying them as simple or composed, ascendants or descendants, consonantes or dissonantes, melodics or harmoncis. Doubts? Comments? Send e-mail to: ivan@venegasmusic.com! Hugs!