## INTERVALS

Intervals refer to the distance between two notes, and there are two parts to describing an interval: 1) the numerical component of the interval and, 2) the quality of the interval.

STEP 1: Determining the numerical component of the interval. Consider the interval below (D and A). To determine the interval between the notes, count the number of notes it takes to go from the lower note to the higher note, including both of the notes in question. In this step, ignore any accidentals (sharps of flats). In the above scenario, the interval between D and A is said to be a 5th apart as there are a total of five notes from D to A.

Note that regardless of whether an accidental (sharps or flats) is present in either the upper or lower note, it does not change the numerical component of the interval. For example, the distance between C and F, and C# and F is still a 4th apart

STEP 2: The next step in describing an interval is to determine the quality of the interval. To do that, form the major scale from the lower of the two notes (if you are note sure how to form major scales yet, check out our lesson here). We will use our original interval of D to A. Hence, as D is the lower of the two notes, form the D major scale. To determine the quality of the interval, compare the interval in question to the major scale formed from the lower of the two notes:

Take note that in this step, the accidentals do matter, unlike in the first step when all accidentals are ignored. In the above scenario, the higher of the two notes can be found in the major scale formed from the lower note (Let's call this Scenario 1). In Scenario 1, the quality of the interval is as follows:

So far, we have determined in the first step that 1) A is a 5th above D, and we have also determined that 2) A can be found in the major scale formed from the lower note, D. Using the table above, the quality of this 5th interval between D and A would therefore be a Perfect interval, and A is said to be a Perfect 5th above D.

By now, you may be wondering, what happens if, in the second step, the higher of the two notes deviates from the major scale formed from the lower note (Let's call this Scenario 2)? For example, if the original interval had been D to Ab instead of D to A?

If the original interval had D to Ab, the interval between them would still be a 5th apart (Recall that in step 1, accidentals do not matter). However, this interval falls under Scenario 2 (when the higher of the two notes deviates from the major scale formed from the lower note). For Scenario 2, the following rules apply:

According to the above diagram,

If a interval deviates from a major interval by -1 semitone, then it becomes a minor interval

If a interval deviates from a major interval by -2 semitones, then it becomes a diminished interval

If a interval deviates from a major interval by +1 semitone, then it becomes an augmented interval

If a interval deviates from a perfect interval by -1 semitone, then it becomes a diminished interval

If a interval deviates from a perfect interval by +1 semitone, then it becomes an augmented interval

Hence, in the case of the interval between D and Ab, Ab deviates from the original A note found in the major scale by -1 semitone. What was originally a perfect 5th interval between D and A, is now a Diminished 5th between D and Ab.

Now that you have learnt about intervals, you are ready to move on to our next lesson on Basic Chords And Triads! If you would like more practice on intervals, email us at PianoAtHomeSG@gmail.com to receive a FREE practice worksheet on intervals, complete with an answer sheet!