Intervals: Introduction
Definition
In this section we will learn about musical intervals. An interval is the distance between two pitches. If these two pitches are played simultaneously, the result is a harmonic interval. (Listen to the harmonic interval formed between C and G in the example below.) If the two pitches are played consecutively (one after the other), the result is a melodic interval, which can occur in an ascending or a descending direction. (Listen to the ascending melodic interval from C to G and the descending melodic interval from G to C in the example below.) In either case, an interval measures the distance between the two pitches.
Harmonic Interval
(Simultaneous pitches)
Melodic interval
(Consecutive pitches)
Ascending
Melodic interval
(Consecutive pitches)
Descending
Of course, there is much more to it than that. Musicians have developed a system of classification for intervals that describes both interval size and interval quality. It takes time and a good deal of practice to learn the system, but it is important to master since a thorough knowledge of intervals is fundamental to an understanding of harmony. In the lessons that follow, we will discuss interval size, interval quality, how to identify intervals, and how to write intervals. You will also have the opportunity to practice identifying different intervals by ear.
Key points
- Two pitches form an intervalThe distance between two notes., which is usually defined as the distance between two notes.
- Melodic intervalsAn interval where two notes are played or sung one note after the other. are played or sung separately, while are played or sung together.
- Every interval has a size and a quality. An interval’s sizeInterval size is written with Arabic numbers (2, 3, 4, etc.); it is the distance between two notes on a staff. is the distance between two notes on a staff—i.e., it is a measurement of the number of lines and spaces between two notes.
- Size is considered genericThe number of scale steps between notes of a collection or scale.. In other words, it doesn’t matter what accidentals you apply to the notes, the size is always the same.
- QualityWhen applied to an interval, the term "quality" modifies the size descriptor in order to be more specific about the exact number of semitones in the interval. When applied to triadic harmony, "quality" refers to the size of the different intervals that make up the harmony. makes an interval specificA combination of size and quality to describe an interval. when used in combination with a size. Unisons, fourths, fifths, and octaves form perfect intervals, while seconds, thirds, sixths, and sevenths form major and minor intervals.
- Any interval can be augmented or diminished. Augmented intervalsIntervals that are one half-step larger than a perfect interval or a major interval. are one half-step larger than a perfect or major interval. Diminished intervalsIntervals that are one half-step larger than a perfect or major interval. are one half-step smaller than a perfect or minor interval.
- Intervals between a unison and an octave are called simple intervalsIntervals with a size an octave or smaller.. Any interval larger than an octave is a compound intervalIntervals with a size an octave or smaller..
- Intervallic inversionOccurs when two notes (such as C and E) are flipped; C (on bottom) with E (above) is an inversion of E (on bottom) with C (above). occurs when two notes are “flipped.” Inverting intervals can be useful when you do not want to work in the key signature of the note that is the original lower note.
- ConsonantA quality in an interval or chord that, in a traditional tonal context, is stable; this stability is the result of its perceived independence from a need to resolve. intervals are intervals that are considered more stable, as if they do not need to resolve, while dissonantA quality in an interval or chord that, in a traditional tonal context, is unstable; this instability is the result of its perceived dependence on a need to resolve. intervals are considered less stable, as if they do need to resolve.