Charles Dodge’s Earth’s Magnetic Field: Realizations in Computed Electronic Sound, was composed in 1970 and was released by Nonesuch. Bell laboratories developed many important technologies that were employed by electronic music composers. A more detailed account of the developments can be found in the annotations of Computer Music, by Nonesuch. One of the first main contributions from Bell labs, in the late 1950’s, was a computer sound synthesis program that could—theoretically—produce any sound. Another main component was the Digital Audio Converters that made it possible to hear the sounds that were being programmed. This translated to the work that was being done at Columbia and Princeton, where composers sought to utilize these developments. Charles Dodge was one of the composers working at Columbia and Princeton that worked also at Bell Laboratories on his music.
With this piece, Charles Dodge mapped magnetic field data to musical sounds. Over the course of a year, 2920 readings were taken of the magnetic field. This was then mapped to a four octave span, or 45 notes (the average span of an instrument). Between different points within this data, interpolations were made to create the other aspects of the music—tempo, dynamics, and register. Here’s part of the readings that he used:
Regardless of the mapping and per-determined form, this piece still flows musically and has some beautifully crafted moments. With lyrical lines and sweeping gestures, the piece brings the data to life. In my opinion, the musical representation of the data can be quite catchy at points.
Here’s a sample of Earth’s Magnetic Field, from roughly eleven minutes into the piece.[audio:http://info.umkc.edu/specialcollections/wp-content/uploads/2014/02/EarthMagField.mp3|titles=Earth’s Magnetic Field.|artists= Charles Dodge]