For centuries, the so-called tempered scale in use in western countries has drastically limited the composer’s and performer’s scope of expression. It should be remembered that the tempered scale is merely a compromise reached to facilitate the manufacture of certain instruments. It can be observed that when a performer is free to do so, i.e. with voice or violin, intervals are produced which are not included in the tempered scale. The result of years of research and experiment in Indian modal music and other musical traditions of the Orient, Alain Daniélou’s book "Sémantique Musicale" advances a revolutionary theory concerning pitch ratios. Without going into detail, the main concepts are as follows :

According to the author, he brain immediately classifies factors 2, 3 and 5 and some - even quite high - multiples or products of the same, but ceases to function when fed with prime numbers higher than 5 . Thus, the human ear identifies and classifies pitch according to base 2, base 3 and base 5 systems. Alain Daniélou consequently recommends dividing the octave into 53 intervals, the ratio of each note (i.e. the ratio of its pitch to the pitch of the keynote) being related to a combination, in fractional form, of the numbers 2, 3 and 5.

Each interval in Alain Daniélou’s scale corresponds to a different feeling and the scale itself could be qualified as "natural", since it is based on simple integer ratios of frequencies found in the prime harmonics of most sounds. In other words, such intervals give rise to definite and apparently universal emotional reactions (cf. Annex 1). Furthermore, according to Alain Daniélou, The Hindu theory concerning shruti, or intervals, and classes of shruti - known as jati, attributes to each interval a well-defined expressive content and classifies the intervals in easily understandable categories, which can only be explained by the nature of the numerical ratios of the cycles 2-3- 5. Moreover, the simpler the fractional ratios (i.e. the fewer multiples and products of 2, 3 and 5 they include), the greater the emotional content of the related intervals.