MUSIC THEORY

Mod 25

• Subject of the Day: Parallel Fifths and Octaves; Hidden Fifths and Octaves
• Reading Assignment: Textbook, pp.78-84
• Written Assignment: Workbook, ex.5-3
• Semester Schedule

Between 2 voices there are three types of motion; 1)contrary, oblique, and similar.  Since independence between the voices is most desirable, the best movement between voices is contrary.  Oblique motion (one voice repeating while the other voice changes) also has an element of independence.  Similar motion, due to its lack of independence may have some awkward combinations.  Good similar motion between voices are parallel thirds and parallel sixths which are very common and desirable. Parallel fourths are not objectionable but are not especially good sounding, either.

                                                        Contrary Motion                        Oblique Motion                                Similar Motion

Parallel octaves (A below), parallel fifths (B),  and parallel unisons (E) are all objectionable and should be avoided.  Parallel octaves are heard when a P8 (or compound P8) occurs between two voices and the same two voices move to form another P8.  Similar situations arise for parallel unisons and parallel fifths.  If one of the fifths between two voices is a diminished fifth, the parallel fifths are OK (F).  An additional precaution  should be noted when a P5 between two voices moves to another P5 between the same two voices but they are approached in contrary motion (D).  This is called consecutive fifths by contrary motions and should be avoided.  Likewise, with the consecutive octaves by contrary motion (C).

The definition of a hidden or direct fifth is a P5 between two voices approached in similar motion.  Hidden octave is a P8 between two voices approached in similar motion.  Hidden fifths and octaves occur regularly between any two voices and normally we ignore their occurence.  However, when these appear between outer voices (bass and soprano in 4 voices), we need to take notice.  If in such a situation the soprano moves by step, the hidden fifth or octave is acceptable.  But if the soprano skips to its note, the resulting hidden fifth or octave is objectionable and shoud be avoided.

If you still have questions, contact Dr. Bartolotta at wbartolo@odu.edu