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).[1]
In India's Carnatic music, this corresponds to Simhendramadhyamam.
In step notation:
or in decimals:
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:
It can also be thought of as Harmonic Minor with a raised 4 in the first octave.