Writing Intervals
  • When writing intervals on the staff, it is common to confuse intervals with the same number of half steps.
  • For example, one may accidentally write C to F# (an augmented fourth) instead of C to Gb (a diminished fifth).
  • Although both intervals sound the same and look identical on the keyboard, one is a fourth and the other is a fifth.
  • Fortunately, an easy three-step process exists to reduce the risk of this mistake.
  • Let's write a minor third from C.
  • First, write the generic interval on the staff. For this example, we will write a generic third.
  • Next, figure out the number of half steps on the keyboard. Since a major third is 4 half steps, our minor third will be 3 half steps.
  • Finally, compare the staff and keyboard results. Add any needed accidentals to the staff.
  • C—Eb is a minor third.
  • For our next example, let's try a major sixth from F#.
  • First, write the generic sixth on the staff.
  • Next, figure out the half steps on the keyboard. A major sixth is 9 half steps.
  • Finally, add any needed accidentals.
  • F#—D# is a major sixth.
  • For our final example, we will write a diminished fifth from B.
  • First, write the generic fifth on the staff.
  • Next, figure out the half steps on the keyboard. Since a perfect fifth is 7 half steps, our diminished fifth has 6.
  • Finally, add any needed accidentals. In this example, no accidental is needed.
  • B—F is a diminished fifth.
  • Use this chart to reference the interval-writing process.
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