Discussion 10c - Error detection

Detection Affection

Parallel Perfect Octaves (PP8):

• What causes this part-writing error?
  • Both tones in our example are the leading tone of I–we have doubled thirds!
• Why is this bad?
  • Lack of voice independency. A bunch of parallel motion can cause voices to bleed together, and then when they separate again it can be jarring to the overall texture
• If you were going to fix this, how would you do it?
  • Have soprano sing a D in the first note of the second measure? (techincally yes, but it makes a jumpier melody which isn’t ideal)
  • In the same place, change the tenor to a D instead of the soprano?
  • Double the G in the lower two voices?
  • Have soprano sing a D on the second and third chords?
  • BASICALLY: fixing the errors is never as simple as you want it, and there’s a bunch of different ways to do it. Fixing them can be…trial and error :)

Parallel Perfect Fifths (PP5):

• Still considered a PP5 even in distant voices?
  • Yes! Any of these movement errors can happen between any 2 voices

Contrary Perfect Fifths and Octaves (CP5, CP8):

• Usually happens when trying to fix a parallel movement error by moving one voice an octave down. It isn’t ideal to sing and usually creates spacing errors as a result
• Red flag: if there’s a HUGE leap in one of the voices, there’s probably a contrary P5 or P8

Unacceptable Unequal Fifths (UU5):

• movement from a d5 to a P5
• must involve the bass
• Red flag: tendency tones not resolving the way they’re supposed to
  • Ex: in C, B and F resolving to C and G. F is the seventh of a G7 chord and is supposed to resolve downward by step to the third of the next chord, but it went up to G instead.
• There is no octaves version of this one, fifths only

Unacceptable Similar Fifths and Octaves (US5, US8):

• The most restrictve of these movement errors, so if you look for the specifics it will be easy to find!
  • Can only happen in the soprano and bass
  • Red flag: Skip of a third or more in the soprano voice + similar motion in soprano and bass
  • Second interval must be a P5 or P8. What matters is what interval it lands on, not what it starts on

Number Detection System

“What is it?”

• A quick method for finding part-writing errors that involves labeling voice movement with numbers and looking for patterns.

Process:

1. For each voice, write an interval number between every note in that voice’s part. The interval number only needs to indicate the quantity of the interval, not the quality or direction. You should be left with a column of four numbers between every stack of notes.
2. Go through each stack of numbers and check for matching numbers within a stack. Check that the voices with matching numbers are not moving in unnacceptable Parallel, Unequal, or Similar motion.
3. Check each stack for pairs of numbers that add to 9. These indicate the presence of Contrary Perfect Octaves.