The Algerian Scale is a scale frequently used in Algerian music. The frequent use of 1.5 steps (a minor 3rd) in the scale contributes to a sound commonly associated with Moorish music.
It is also defined as an eleven note scale with two augmented seconds. Jacques Ibert first used this definition in Escales (1924).[3]
This formula gives the first octave only. In the second octave, the third step is 1 rather than 1.5, followed by a step of 1 rather than 0.5. This may be seen in images to the right. In the one on the bottom (with the three-octave spanning scale, Fischer 1996), the lower octave shows an F♯ while the upper octave shows an F natural.
This can also be notated as degrees in relation to the root note:
First octave: 1 2 ♭3 ♯4 5 ♭6 7 8
Second octave: 1 2 ♭3 4 5 ♭6 7 8
It can also be thought of as Harmonic Minor with a raised 4 in the first octave.
Sources
^Middlebrook, Ron (1984). Scales and Modes in the Beginning, p.125. ISBN0-89898-151-4.
^Robert Fink, Robert Ricci (1975). The Language of Twentieth Century Music: A Dictionary of Terms, p.3. Schirmer Books. ISBN0-02-870600-5, ISBN978-0-02-870600-9.