کارشناس ارشد موسیقی، دانشکده موسیقی، دانشگاه هنر تهران
عنوان مقاله [English]
This paper intends to study attraction theory which it has been published in a book entitled new method of music performance principles. It should note that mentioned book has been selected as the best book in 21 festival for year book in Islamic republic of Iran. At first some these drawbacks will be considered regarding to scientific rules then we find that the frequency ratio of sounds in this book is not correct in comparing other books. so modified theory shall be presented to estimate musical interval which its origin includes medium and complete distances such as octave, perfect fifth and perfect fourth which are the best sound of musical intervals. Propounding drawbacks: 1-In sound attraction systems. All of estimations belong to ‘William Holder’ have been used but no reference and including drawbacks.2- Attraction system is resulted from hypoionian mode no Major scale.3- If we put altered notes in attraction circle, sounds are included in their circles. Draw back no 1:We find that the aim of book writer is presenting new method of musical performance principle belong to Holder’s comma but there is no difference between (si and do) and (mi and fa) and their frequency ratios which are considered as diatonic semitone and equals 4 commas of Holder while in Lotfi’s theory the semitone interval of (si and do) .has frequency rate equals 4 commas of Holder. Draw back no 2: In new method of musical performance principle book, writing scale, includes C Major and consist of two tetra chord and resulted from sun and planets of solar system. This kind of writing is resulted from hypoionian and Ionian modes but the central sound in hypoionian and Ionian is called finalis note tonic note. Also it should be noted that the introduction of M?hur (Do) which is Iranian musical instrument is written like this. Draw back no 3:Now with considering this subject that in musical tuning system of Holder, the ratios of chromatic semitone equals 5 comma and the ratio of diatonic semitone equals 4 comma and we see that most of sounds will put in their orbit which this differs from what author of sound attraction theory book has been noted. Modified theory based on scientific principles: In this order mentioned theory has two ascendant and descendant tetra cords. Ascending tetra chord sound have ratios such as 10/9, 9/8, 16/10 and descendant tetra chord sounds have ratios such as 21/20, 10/9, 9/8 in this theory exist 3kinds of tone and the semitones respectively. Kinds of tone: 1- Super tone, has ratio 8/7 (58 savart, 231.1 cent) 2-Major tone has ratio as 9/8 (51 savart, 203.9 cent) 3- minor tone to has ratio as 10/9 (46 savart, 182.4 cent) Kinds of semitone: 1-Ascending diatonic half tone has ratio as 16/15 (28 savart, 111.7 cent) 2- Descending diatonic semitone has ratio as 21/20 (21 savart, 84.4 cent) 3-Chromatic semitone has ratio as 15/14 (30 savart, 119.4 cent).Figures in this paper can be useful to understand this scientific estimations and theory.