PLOrk2009/TheodorPopovFinalProject

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The Theremin Harmonizer

For my final project I built several variations of a harmonizing instrument that takes a pitch input and creates harmonies around it. It is designed to work particularly well with a B3 Deluxe Theremin. However, you can try it at home by whistling with similar results.

Why Theremin?

Patented in the early 1900s by a Russian genius, the theremin is the first electronic instrument. Its invention stimulated creativity and developments that revolutionized the way we look at music: practically everything is possible for a composer nowadays.

The theremin, however, fell into relative oblivion – few know of its existence today and even fewer work actively towards its development as a musical instrument. One major lack, for instance, is the inability of the player to produce more than one pitch at the same time. True, it is a melodic instrument, but unlike most other melodic instruments it is not capable of “cheats” to create harmony (arpeggios are very difficult to do and notes can not be sustained after they have been played).

One solution to these issues can be found in the just released by Moog Music model: the Etherwave Plus which gives the player unmatched before freedom of modification of the sound the instrument produces. Another one is offered by my final project.

The Harmonizer

I used ChucK and the MiniAudicle to create code that analyzes the sound input and determines the fundamental of the pitch by looking at the peak of the spectrum. Then it creates musical intervals around that pitch and plays back different harmonies. The code is easy to work with and allows for freedom of modification because one can just comment(uncomment) the undesired(desired) intervals.

There are several versions of the code that you can download here. The basic one builds a diminished seventh cord over the input pitch. There are also variations for a major and minor triads. Finally, the “Rule of the Octave” harmonizes the chromatic scale from C4 to C5 with suitable chords within a C major context.

Disclaimer

The Harmonizer works well for clear-pitched instruments such as the B3 Theremin. However, it doesn’t do a very good job of determining the fundamental of rich timbre instruments because it is not always the highest peak in the spectrum. For example if you tried playing the piano, it would not harmonize the tones you think it should.

The Results

The following short clips show the results of this harmonizing experiment. Here are three conclusions that can be reached:

  • 1) The "Rule of the Octave" does a fairly good job of harmonizing a glissando ascending octave (although some leading tones don't resolve properly).
  • 2) The diminished chords version is good for creating spooky sounds reminiscent of 60s horror movies.

Overall, this harmonizing instrument is far from perfect but it is a good foundation to build on.

Acknowledgments

Thank you, Rebecca, for answering my many (and sometimes not so intelligent) questions. And thank you everyone else in PLOrk - this has been one of the most fun classes I have taken so far.

The Honor Code

This project represents my own work in accordance with University regulations. Theodor Popov'11