Ludwig van Beethoven died before he completed what would have been his tenth and final symphony. A team of computer scientists and music scholars approximated the music that might have been.

What’s new: The Beethoven Orchestra in Bonn performed a mock-up of Beethoven’s Tenth Symphony partly composed by an AI system, the culmination of an 18-month project. You can view and hear the performance here.

How it works: The master left behind around 200 fragmentary sketches of the Tenth Symphony, presumably in four movements. A human composer in 1988 completed two movements, for which more source material was available, so the team set out to compose two more.

  • Matthias Röder, director of the Karajan Institute, which promotes uses of technology in music, led musical experts in deciding how the sparse contents of the remaining sketches might fit into a symphonic format. Meanwhile, Rutgers University professor Ahmed Elgammal built an AI system to expand the sketches into a fully orchestrated score.
  • Elgammal adapted natural language models to music, he told The Batch. The system included components that generated variations on melodic themes, harmonized the results, created transitions, and assigned musical lines to instruments in the orchestra.
  • He trained the models first on annotated scores music that influenced Beethoven, later on the composer’s own body of work. To train the melodic model, for instance, he annotated passages of theme and development. Then he fed the model thematic material from the sketches to generate elaborations on it.
  • The system eventually generated over 40 minutes of music in two movements.

Everyone’s a critic: Composer Jan Swafford, who wrote a 2014 biography of Beethoven, described the finished work as uninspired and lacking Beethovenian traits such as rhythms that build to a sweeping climax.

Behind the news: In 2019, Huawei used AI powered by its smartphone processors to realize the final two movements of Franz Schubert’s unfinished Eighth Symphony. The engineers trained their model on roughly 90 pieces of Schubert’s work as well as pieces written by composers who influenced him. A human composer cleaned up the output, organized it into sections, and distributed the notes among various instruments.

Why it matters: AI is finding its way into the arts in a variety of roles. As a composer, generally the technology generates short passages that humans can assemble and embellish. It’s not clear how much the team massaged the model’s output in this case, but the ambition clearly is to build an end-to-end symphonic composer.

We’re thinking: Elgammal has published work on generative adversarial networks. Could one of his GANs yield Beethoven’s Eleventh?


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