How Musicologists and Scientists Used AI to Full Beethoven’s Unfinished tenth Symphony



When Ludwig van Beethoven died in 1827, he was three years faraway from the completion of his Ninth Symphony, a piece heralded by many as his magnum opus. He had began work on his tenth Symphony however, as a consequence of deteriorating well being, wasn’t capable of make a lot headway: All he left behind have been some musical sketches.
Ever since then, Beethoven followers and musicologists have puzzled and lamented over what may have been. His notes teased at some magnificent reward, albeit one which appeared ceaselessly out of attain.
Now, due to the work of a group of music historians, musicologists, composers and pc scientists, Beethoven’s imaginative and prescient will come to life.
I presided over the bogus intelligence aspect of the undertaking, main a gaggle of scientists on the inventive AI startup Playform AI that taught a machine each Beethoven’s total physique of labor and his inventive course of.
A full recording of Beethoven’s tenth Symphony is ready to be launched on Oct. 9, 2021, the identical day because the world premiere efficiency scheduled to happen in Bonn, Germany—the end result of a two-year-plus effort.
Previous Makes an attempt Hit a Wall
Round 1817, the Royal Philharmonic Society in London commissioned Beethoven to jot down his ninth and tenth symphonies. Written for an orchestra, symphonies typically comprise 4 actions: the primary is carried out at a quick tempo, the second at a slower one, the third at a medium or quick tempo, and the final at a quick tempo.
Beethoven accomplished his Ninth Symphony in 1824, which concludes with the timeless “Ode to Pleasure.”
However when it got here to the tenth Symphony, Beethoven didn’t go away a lot behind, apart from some musical notes and a handful of concepts he had jotted down.

A web page of Beethoven’s notes for his deliberate tenth Symphony. Picture Credit score: Beethoven Home Museum, CC BY-SA
There have been some previous makes an attempt to reconstruct components of Beethoven’s tenth Symphony. Most famously, in 1988, musicologist Barry Cooper ventured to finish the primary and second actions. He wove collectively 250 bars of music from the sketches to create what was, in his view, a manufacturing of the primary motion that was trustworthy to Beethoven’s imaginative and prescient.
But the sparseness of Beethoven’s sketches made it unimaginable for symphony specialists to transcend that first motion.
Assembling the Staff
In early 2019, Dr. Matthias Röder, the director of the Karajan Institute, a company in Salzburg, Austria, that promotes music know-how, contacted me. He defined that he was placing collectively a group to finish Beethoven’s tenth Symphony in celebration of the composer’s 250th birthday. Conscious of my work on AI-generated artwork, he needed to know if AI would be capable of assist fill within the blanks left by Beethoven.
The problem appeared daunting. To tug it off, AI would want to do one thing it had by no means accomplished earlier than. However I stated I might give it a shot.
Röder then compiled a group that included Austrian composer Walter Werzowa. Well-known for writing Intel’s signature bong jingle, Werzowa was tasked with placing collectively a brand new form of composition that will combine what Beethoven left behind with what the AI would generate. Mark Gotham, a computational music knowledgeable, led the trouble to transcribe Beethoven’s sketches and course of his total physique of labor so the AI may very well be correctly educated.
The group additionally included Robert Levin, a musicologist at Harvard College who additionally occurs to be an unbelievable pianist. Levin had beforehand completed numerous incomplete 18th-century works by Mozart and Johann Sebastian Bach.
The Venture Takes Form
In June 2019, the group gathered for a two-day workshop at Harvard’s music library. In a big room with a piano, a blackboard and a stack of Beethoven’s sketchbooks spanning most of his recognized works, we talked about how fragments may very well be changed into an entire piece of music and the way AI may assist clear up this puzzle, whereas nonetheless remaining trustworthy to Beethoven’s course of and imaginative and prescient.
The music specialists within the room have been wanting to study extra in regards to the form of music AI had created up to now. I informed them how AI had efficiently generated music within the fashion of Bach. Nevertheless, this was solely a harmonization of an inputted melody that seemed like Bach. It didn’t come near what we would have liked to do: assemble a whole symphony from a handful of phrases.
In the meantime, the scientists within the room—myself included—needed to study what kind of supplies have been obtainable, and the way the specialists envisioned utilizing them to finish the symphony.
The duty at hand finally crystallized. We would want to make use of notes and accomplished compositions from Beethoven’s total physique of labor—together with the obtainable sketches from the tenth Symphony—to create one thing that Beethoven himself may need written.
This was an amazing problem. We didn’t have a machine that we may feed sketches to, push a button and have it spit out a symphony. Most AI obtainable on the time couldn’t proceed an uncompleted piece of music past a number of further seconds.
We would want to push the boundaries of what inventive AI may do by educating the machine Beethoven’s inventive course of—how he would take a number of bars of music and painstakingly develop them into stirring symphonies, quartets, and sonatas.
Piecing Collectively Beethoven’s Inventive Course of
Because the undertaking progressed, the human aspect and the machine aspect of the collaboration advanced. Werzowa, Gotham, Levin, and Röder deciphered and transcribed the sketches from the tenth Symphony, attempting to know Beethoven’s intentions. Utilizing his accomplished symphonies as a template, they tried to piece collectively the puzzle of the place the fragments of sketches ought to go—which motion, which a part of the motion.
They needed to make selections, like figuring out whether or not a sketch indicated the place to begin of a scherzo, which is a really vigorous a part of the symphony, usually within the third motion. Or they may decide {that a} line of music was doubtless the idea of a fugue, which is a melody created by interweaving components that every one echo a central theme.
The AI aspect of the undertaking—my aspect—discovered itself grappling with a spread of difficult duties.
First, and most essentially, we would have liked to determine methods to take a brief phrase, and even only a motif, and use it to develop an extended, extra difficult musical construction, simply as Beethoven would have accomplished. For instance, the machine needed to find out how Beethoven constructed the Fifth Symphony out of a fundamental four-note motif.

Subsequent, as a result of the continuation of a phrase additionally must observe a sure musical type, whether or not it’s a scherzo, trio, or fugue, the AI wanted to study Beethoven’s course of for creating these kinds.

The to-do checklist grew: We needed to educate the AI methods to take a melodic line and harmonize it. The AI wanted to discover ways to bridge two sections of music collectively. And we realized the AI had to have the ability to compose a coda, which is a section that brings a piece of a chunk of music to its conclusion.

Lastly, as soon as we had a full composition, the AI was going to have to determine methods to orchestrate it, which entails assigning totally different devices for various components.
And it needed to pull off these duties in the way in which Beethoven may accomplish that.
Passing the First Massive Take a look at
In November 2019, the group met in individual once more—this time, in Bonn, on the Beethoven Home Museum, the place the composer was born and raised.
This assembly was the litmus check for figuring out whether or not AI may full this undertaking. We printed musical scores that had been developed by AI and constructed off the sketches from Beethoven’s tenth. A pianist carried out in a small live performance corridor within the museum earlier than a gaggle of journalists, music students, and Beethoven specialists.

Journalists and musicians collect to listen to a pianist carry out components of Beethoven’s tenth Symphony. Picture Credit score: Ahmed Elgammal, CC BY-SA
We challenged the viewers to find out the place Beethoven’s phrases ended and the place the AI extrapolation started. They couldn’t.
Just a few days later, certainly one of these AI-generated scores was performed by a string quartet in a information convention. Solely those that intimately knew Beethoven’s sketches for the tenth Symphony may decide when the AI-generated components got here in.
The success of those checks informed us we have been heading in the right direction. However these have been simply a few minutes of music. There was nonetheless rather more work to do.
Prepared for the World
At each level, Beethoven’s genius loomed, difficult us to do higher. Because the undertaking advanced, the AI did as nicely. Over the following 18 months, we constructed and orchestrated two total actions of greater than 20 minutes apiece.
We anticipate some pushback to this work—those that will say that the humanities ought to be off-limits from AI, and that AI has no enterprise attempting to copy the human inventive course of. But in relation to the humanities, I see AI not as a alternative, however as a device—one which opens doorways for artists to specific themselves in new methods.
This undertaking wouldn’t have been doable with out the experience of human historians and musicians. It took an immense quantity of labor—and, sure, inventive considering—to perform this purpose.
At one level, one of many music specialists on the group stated that the AI reminded him of an keen music pupil who practices day by day, learns, and turns into higher and higher.
Now that pupil, having taken the baton from Beethoven, is able to current the tenth Symphony to the world.

The piece above is a variety from Beethoven’s tenth Symphony. YouTube/Fashionable Recordings, CC BY-SA 3.38 MB (obtain)
This text is republished from The Dialog below a Inventive Commons license. Learn the unique article.
Picture Credit score: Circe Denyer