| 摘要 |
Marks (2) on a first panel (A) logarithmically represent the heights of the non-altered notes on a musical scale. A second panel (B) includes two fixed indices (11) separated, in abscissa and in ordinate, by the same distances as two marks corresponding to two distant notes of an octave. Mobile indices (15) are arranged between the fixed indices. The second panel (B) can be arranged at all the positions where each fixed index (11) coincides with a mark (2) as well as in positions offset on the ordinate, by virtue here of a set of tenons (4) interacting with apertures formed in the fixed indices (11). It allows the student to comprehend the modes, in a concrete way, on the basis of a familiar scale. <IMAGE>
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