13 years ago

Intonation of North Indian Classical Music: working with the MMA

Bernard Bel
The Melodic Movement Analyzer (MMA), a melodic analyzer featuring 1 cent accuracy on 52 samples per second, was designed and built in 1980 by Bernard Bel, a French electronics/computer engineer. The next unit after the prototype was installed in the laboratory of the National Centre for the Performing Arts in Bombay, as per an agreement with the International Society for Traditional Arts Research (ISTAR) supported by the Ford Foundation.

This video shot and edited in 1984 by Mr. D.B. Biswas, the director of NCPA, demonstrates initial findings and the operational mode of MMA linking Bel's fundamental pitch extractor to an Apple III computer running analysis software. It features a discussion between Bernard Bel and Joep Bor, both research fellows of the ISTAR.

The demo starts with a comparative analysis of the tonal pattern of note Ga in raga Darbari Kanada (vocal and instrumental) in various melodic and performance contexts: Ustad Asad Ali Khan and his father Sadiq Ali Khan playing the rudra vina. Another demo is dealing with Raga Jaunpuri sung by Ms Bhupender Seetal, a disciple of Pt Dilip Chandra Vedi.

The last part deals with the statistical analysis of the microtonal scale displayed as a tonagram (following an idea of Emile Leipp). This analysis makes it possible to highlight and measure dissimilarities between ragas sharing the same scale. It has been later used for automatic raga classification on the basis of their acoustic signal.

MMA performed 416 measurements per second with 1 per 1000 accuracy on the period. Data were stored on a track of the magnetic tape using square-Miller encoding and later transfered to floppy disks by an Apple II computer. Tape transport was optimized by a phase-frequency discriminator. Analysis software was written in 6502 machine language and compiled BASIC.

A recent answer to some questions raised in this video will be found in Wim van de Meer's article “Gandhara in Darbari Kanada, the mother of all shrutis?” (http://thoughts4ideas.eu/gandhara-in-darbari-kanada-the-mother-of-all-shrutis/)

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