A musical scale is a set of musical notes ordered by pitches. If we order the notes of a scale by increasing pitches, we call it an ascending scale. If we order the notes of a scale by decreasing pitches, we call it a descending scale. Most of them contain the same note names when ascending and descending. But some of them may contain different accidentals when descending other than when ascending. A melodic minor scale is an example of this. Knowing about musical scales is so important for playing music. Because we build most of the melodies and harmonies of a musical work upon the scales. In other words, when we play a piece of music, we actually play the notes of a single scale or a combination of scales. We represent musical scales with key signatures on a staff.
Scales usually span a single octave. On higher and lower octaves, the pattern repeats. We identify scales by half or whole steps between their successive notes.
Types of Musical Scales
We classify musical scales by either the intervals they contain or the number of different pitch classes they contain.
Scales Classified By The Intervals They Contain
The musical scales which are classified by the intervals they contain are diatonic, chromatic and whole tone scales.
1. Diatonic Scales
A diatonic scale is a heptatonic scale which has seven unique pitches per octave. Between these pitches are five whole steps and two half steps in each octave. Two half steps of a diatonic scale are separated from each other by either two or three whole steps depending on their position in the scale. This pattern allows a diatonic scale to span more than one octave.We can describe a diatonic scale as two tetrachords and a whole step between them.
Tetrachords consist of four notes and three steps between them. The patterns of steps of tetrachords vary by scales. Most common diatonic scales are major scales and natural minor scales.
a. Major Scales
Variations of Natural Minor Scales
There are two common variations of natural minor scales. These are harmonic minor scales and melodic minor scales.
So far, you have learned about scales that are classified by the intervals they contain. On my next articles, I’ll tell you about the scales that are classified by the number of different pitch classes, they contain.
Scales Classified By The Number Of Different Pitch Classes They Contain
Another way of classifying the scales is the number of different pitch classes they contain.
1. Monotonic Scale
Monotonic scale is a musical scale that consists of only one note. In spite of this deliberate fixed note, we also consider monotonic scale as a musical form. It has a limited use in liturgy and we use it as an effect in modern art music.
2. Ditonic, Tritonic, Tetratonic Scales
Ditonic scale has two notes. Tritonic scale has three notes. Tetratonic scale has four notes. The use of these three kinds of scales is mostly limited to prehistoric, primitive music.
4. Hexatonic Scale
5. Heptatonic Scale
A heptatonic scale is a musical scale that consists of seven unique notes. The most common examples of heptatonic scales are major scales, natural minor scales, melodic minor scales and harmonic minor scales.
6. Octatonic Scale
An octatonic scale is a musical scale that consists of eight unique notes. This scale is not common.