Clever search engine finds variations on a melody. Software categorises Dutch folksongs

5 October 2010

A new search engine makes it possible to automatically compare melodies and show the similarities and differences between them. The scientist Peter van Kranenburg developed the software so as to find variants of Dutch folksongs in transcriptions of thousands of tape recordings.

Mr Van Kranenburg will be receiving his doctorate at Utrecht University on Monday 4 October 2010.
Traditional folksongs often have dozens of variants because of the way they have been passed down through the centuries from generation to generation. The Meertens Institute holds a large number of these melodies, collected by Ate Doornbosch for his much-loved radio programme Onder de groene linde [Under the Green Linden Tree]. More than 5000 of these melodies have been transcribed into musical notation. By identifying variants of the same melody in the transcriptions, the search engine enables Peter van Kranenburg to search through and categorise these folksongs.

Melodies one below the other

The software searches for similar sections of melodies and places them one below the other. The extent to which they can be aligned indicates how similar they are (see the illustration). Examining the average level of correspondence makes it possible to link melodies to the original songs even though some sections have a different rhythm, pitch, or time signature.

Whistling will be enough

The search engine makes it possible to discover variants of a folksong among thousands of other melodies or to identify an unknown melody. It may become possible for consumers to use the search engine to find music. All that will be necessary is for reliable software to be developed to convert music into notation. "If you don't know the name of a song," says Peter van Kranenburg, "it will basically be enough just to whistle it. Even if the melody is not exactly the same, the search engine will find the melody that displays the greatest similarity."

Illustration (click to enlarge) 

Vergelijking van melodieen 

Two variants of the same song have been placed one below the other by the computer. The two staves in between show the comparison between the variants. The figures with the notes show how well they correspond.
See also the Dutch folksong database at the Meertens Institute.

More information

Robert Kerst, science information officer, Faculty of Science, Telephone +31 (0)30 2531 422, E-mail r.kerst@uu.nl.
If no answer: Roy Keeris, press officer Utrecht University Telephone +31 (0)30 2532 411, E-mail r.b.keeris@uu.nl.