This randomly generated multichoice quiz tests your knowledge of chromatic post-tonal fundamentals (pitch-class integers, ordered pitch intervals, and interval classes).


  • Pitch-class integer: numerical index of a pitch-class, with C=0 up to B=11
  • Ordered pitch interval (OPI): the number of semitones between two ordered pitches. A negative number indicates a descending interval.
  • Interval class (IC): the smallest number of semitones between two unordered pitch-classes (between 0 to 6)
  • The test is timed from when you start. You should be aiming to complete this test in under 4 minutes.

    0–2 mins = Professional  2–4 mins = Good  4–6 mins = Average  6–8 mins = Sluggish  8 mins or more = Too slow.