Overview 10c - Error detection

We have now studied the full array of part-writing errors for four-part chorale style compositions. Because there are so many possible errors, it can feel overwhelming to begin looking for errors, and it is easy to miss errors in long examples. I have developed a method for systematically identifying part-writing errors, and it not only helps to limit errors, it also helps students to understand the vertical and horizontal interactions that create part-writing errors.

Follow the steps from the list below when searching for errors. The next page gives specific examples of how to use this methodology for numbers 5 through 8.

1. Voice-crossing
   • Exception: alto and tenor may cross briefly if musically necessary
2. Spacing: In a four-part texture, are the top three voices within an octave of the adjacent voices?
3. Range
4. Doubling
5. Similar 5ths and 8ves
   • Follow the soprano line looking for leaps
   • When a leap is found, look to see if there is similar motion in the bass (not parallel)
   • Determine the interval between the outer voices of the second chord. - If this interval is either a P5 or P8, there is a similar 5th or 8ve.
6. Parallel Perfect 5ths and 8ves
   • Determine the interval between each pitch horizontally (melodically – NOT within each chord (vertically)
   • If one of the new vertical stacks of four intervals (numbers only) contains two matching numbers, check to see if the intervals within each chord (vertically) are P5s or P8s.
     • With triads, P5s must always have the root of the chord on the bottom of a major or minor chord. No other combination or chord can produce a P5.
     • P8s must come from doubled voices moving to doubled voices
   • If there are two consecutive P5s or P8s, those are parallel 5ths or 8ves.
7. Unacceptable Unequal 5ths
   • Should be found while looking for parallel 5ths using same method as above.
   • When completing step 2, if a d5 moves to a P5 and it involves the bass line, this is unacceptable unequal 5ths
8. Contrary Perfect 5th and 8ves
   • After the first part of the parallel perfect 5ths/8ves instructions, look for inverted pairs of numbers (e.g. 2 and 7, 3 and 6, 4 and 5) within each number stack
   • If one of the new vertical stacks contains one of these inversion pairs, check to see if the intervals within each chord (vertically) are P5s or P8s.
   • With triads, P5s must always have the root of the chord on the bottom of a major or minor chord. No other combination or chord can produce a P5.
   • P8s must come from doubled voices moving to doubled voices
   • If there are two consecutive P5s or P8s, those are contrary 5ths or 8ves.