Identifying Intervals – Cheat Sheet

Music Theory II Identifying Intervals - CHEAT SHEET 1. Obtain the Placeholder No matter what interval in question is, always start with the placeholder! I define the placeholder as the "rough draft" pitch that is the correct interval above/below your given pitch. For example, if the questions asks for a Perfect 5th above C, you immediately need to find the 5th note above C, and write it on the staff. Don't wory about half-steps, or whether or not it's G#, Gb or G natural. Just put the G down on the staff, because it is the 5th note from C! This prevents you from writing down the wrong pitch, and it makes it a lot easier to calculate the half-steps required for the correct interval quality (like major, minor or diminished). Remember, although C# and Db sound the same, they are written differently, and only one of them is a perfect 5th above F#. Unison (Prime) 2nd 3rd 4th 5th 7th 8th Octave 2. Determine the interval quality using half-steps Once your placeholder is in tact, now you need to check to see whether or not the interval contains the correct amount of half-steps. If not, you'll need to alter the placeholder, using sharps or flats. First, check your chart of Major/Perfect half-steps to see how many half-steps your interval should contain. Then, using your keyboard sheet, count the half-steps from the original note to the placeholder. Make sure your starting note counts as zero, and that you are ascending or descending chromatically (which means using both the black and the white keys). If your interval contains the correct amount of half-steps (Ex. DA, Perfect 5th = 7 half-steps), then you're all set. If not, you may need to raise or lower your new note to match the correct amount of half-steps (Ex. F→ B, is NOT a Perfect 4th = 5 half-steps. B must become Bb.) Refer to the chart below to help you identify your intervals properly. Major/Perfect Interval Half-Step Formulas Perfect Unison = 0 half-steps Perfect 5th 7 half-steps Major 2nd = 2 half-steps Major 6th = 9 half-steps Major 3rd = 4 half-steps | Major 7th = 11 half-steps Perfect 4th = 5 half-steps | Perfect Octave= 12 half-steps Music Theory II Identifying Intervals - CHEAT SHEET (Page 2) 3. Deciphering advanced Interval Qualities (Minor/Augmented/Diminished) Instead of writing down and attempting to memorize three additional sets of half-step requirements for new interval qualities, we can simply learn the rules for altering the intervals we do know really well: Major and Perfect. Study and memorize the graphs below. (Unison, 4ths, 5ths, and Octaves) Diminished ← Perfect → Augmented -1 Half-step ← Default → + 1 Half-step (2nds, 3rds, 6ths, and 7ths) Diminished Major → Augmented Minor -1 Half-step (again) -1 Half-step ← Default → + 1 Half-step Here's how it works. Use the top graph for dealing with perfect intervals such as unisons, 4ths, 5ths and octaves. Use the bottom graph when dealing with major intervals, such as 2nds, 3rds, 6ths and 7ths. Once you have the respective graph, follow the arrows in the direction of the interval. For example, if you needed an augmented 6th above F, you would start with 9 half-steps, and then follow the arrow to the right, adding one half-step, meaning an augmented 6th would require 10 half-steps. Everytime you follow an arrow, you add or subtract a half-step from the original formula. Augmenting intervals adds a half-step, and Diminishing/minoring intervals subtract one half-step each. For example, if you're looking for a diminished 3rd, first you must find the half-steps in a regular major 3rd, which is 4 half-steps. Because you must go to the left TWO arrows to get to diminished, you will subtract 2 half-steps. However, if your interval was a diminished 5th (a perfect interval), you would only subtract one half-step, as there is only one arrow in either direction when it comes to Perfect intervals.