Monday, March 2, 2015

Musical symmetry analysis methodology

Here is a bird’s eye view of the musical symmetry analysis method that was used to present these posts:

  1. Though Raja’s compositions run to over 4,500, a database of 1.600 were considered for this analysis (a 30% sample of the population). The sample set has all the languages set to music by Raja other than Marathi
  2. A scan of the 1,600 interludes are done to isolate interludes that are heavily loaded with C&R arrangements (usual and unusual)
  3. Only interludes that have only C&R arrangements with or without musical bridges qualify. There are a number of interludes where C&R arrangements are a small part of it – they do not qualify 
  4. The qualified list of these musical pieces, about 150 of them, are isolated for further analysis
  5. The qualified list is scanned in a detailed fashion to  identify the instruments that are being used in these compositions
  6. Any non C&R arrangements that appear in these compositions are documented as well as the  ‘musical bridges’ to see if they can potentially demonstrate any symmetry around them
  7. The musical pieces that finally qualify are classified into the number of instruments used in the composition, along with the type of symmetry


In order to facilitate easy demonstration of symmetry, there are a set of naming conventions that will make the understanding of musical symmetry easy.

Instrument short form
Instrument detailed form
Be
Bells
Br
Bridge (musical)
Co
Conga
Ch
Chorus
Dr
Drums
Fl
Flute
Gu
Guitar
Pi
Piano
San
Santoor
Sax
Saxaphone
Sh
Shehnai
Si
Sitar
So
Solo Violin
Sy
Synthesizer
Ta
Tabla
Tr
Trumpet
Ve
Veena
Vi
Violins
Vo
Voice

For example, here is an example of how a potential interlude will be documented when we look for symmetry:

(Vi-Fl) x2
(Fl-Gu) x2
Sy bridge
(Gu-Fl) x2
(Fl-Vi) x2

The way to read this is as follows:
  1. Firstly, the musical piece starts with two call and response arrangements between Violin and Flute arranged back to back
  2. Secondly, it is followed by two call and response arrangements between Flute and Guitar arranged back to back
  3. Thirdly, there is a musical bridge for a few bars played with synthesizer
  4. Fourthly, it is followed by two call and response arrangements between Guitar and Flute arranged back to back
  5. Finally, it is followed by two call and response arrangements between Flute and Violin arranged back to back
If you now look at both sides of the bridge, the C&R components have perfect reflection symmetry. This is a case of bridge based perfect symmetry with three instruments. You do not count the instrument that plays the bridge piece. In order for the reader to understand the symmetry easily, I also plan to use a more cryptic notation: 2+2+b+2+2. Each number represents a count of the  C&R arrangement occurences. You can easily see the reflection symmetry on both sides of the bridge with this notation.