Audio: pentatonic scale (0:08)
pentatonic scale plays a melody recorded on a semi-acoustic guitar. The sound has been high-pass filtered to get rid of low-frequency booms and compressed. A little reverb has been added as well. The pentatonic scale figure shows the melody in the score is in the key of A minor pentatonic.
A pentatonic scale is a scale with five notes.
The minor pentatonic scale is a popular five note scale. It is constructed from a series of consecutive perfect fifths. Starting from the note C, for example, results in the series of perfect fifths, CGDAE. Rearranging the notes in alphabetical order results in ACDEG, which is the scale of A minor pentatonic.
Eb minor pentatonic is an easy scale on the piano. It consists of five consecutive black notes.
One of the most interesting features of the minor pentatonic is that it does not contain a tritone. A tritone is a feature in all the modes, it disappears in the pentatonic scale.
The minor pentatonic scale is also known as the blues scale. However, commentators differ over the actual pitches of the notes and whether a blues scale is pentatonic with 5 notes, hexatonic with 6 notes, or heptatonic with 7 notes.
The pentatonic scale example illustrates an interesting issue: the treatment of a note with variable pitch. On a guitar, the pitch of a note can be altered by bending a string up or down by as much as a whole tone. Pitch bending is possible on other instruments too, such as the harmonica and the sax, it is impossible on instruments such as the piano. Pitch bending is variously described as a slur or portamento or vibrato. A similar effect that blurs the pitch of a note is a glide or glissando, which is achieved by sliding a finger up or down a string. There is even a special term, blue note, used to describe a note that is slightly variable in pitch. Notating a bent note is always a compromise. The exact amount of pitch bend can and does vary depending on the performer. The best that can be done is to use an articulation mark in the score, such as the wiggly vibrato symbol in the pentatonic scale score.
One of the benefits of writing music with a small scale is that it is a good way to discover new relationships between notes and keys. For example, the major and minor pentatonic scales are both constructed from four consecutive perfect fifths. Starting on the note C, four consecutive fifths produces the notes G, D, A and E. Rearranging these notes with C as the tonic results in the C major pentatonic scale, CDEGA. Rearranging them with A as the tonic results in the A minor pentatonic scale, ACDEG. The minor pentatonic and major pentatonic scales are sort of related modes, in other words.
Another benefit of writing small scale music is that it brings the rhythm of the music into sharp relief.
Small scales with less than five notes are rare but minimalists may be attracted by the monotonic scale which has only one note.