Artificial music: The computers that create melodies

When Peter Russell first heard the unusual music, he was pleasantly surprised. It was a “delightful piece of chamber music”, he wrote, reminiscent of French pieces written in the early 20th Century. “After repeated hearings, I came to like it.”
What Russell, a musicologist, didn’t know was that the score titled Hello World had actually been composed much more recently by a computer called Iamus. Other listeners in blind tests have been similarly fooled. (Why not listen to it yourself as you read this article?)
Iamus is the creation of computer scientist Francisco Vico and his collaborators at the University of Malaga in Spain. It also has a younger sibling, called Melomics109, which composes ‘popular’ music.
You might think that any serious composers would turn up their noses at music made by a computer algorithm. But a few are already taking Iamus’s ideas very seriously. In 2012, a CD showcasing Iamus’s compositions featured performances by some of the world’s top musicians, including the London Symphony Orchestra. One of the other musicians to appear on the recording was Gustavo Diaz-Jerez, a composer and concert pianist at the Centro Superior de Música del País Vasco, in Spain, who is even using Iamus to write an opera that premieres next year.
No previous attempts to make music by computer – and there have been many, dating back to the early days of computation – have been afforded such serious attention.

Even a cursory listen to Iamus is likely to persuade sceptics that it has come a long way from earlier efforts at computer-composed music such as “Emily Howell”, a program devised by American music professor David Cope. The key to Iamus’s success is an algorithm that mimics the process of natural selection. It takes a fragment of music (itself generated at random), of any length, and mutates it. Each mutation is assessed to see whether it conforms to particular rules – some generic, such as that the notes have to be playable on the instrument in question, others genre-specific, so that features like the melodies and harmonies fit with what is typical for that style. Little by little, the initial random fragment becomes more and more like real music, and the ‘evolutionary process’ stops when all the rules are met. In this way, hundreds of variants can be generated from the same starting material.
In a sense, these algorithms are not doing anything so very different from the way composers have always composed. Composing fugues, for example – which has been done from the Baroque to the modern era – involves taking a small melodic idea and applying permutations and rules that extend, develop and interweave it in overlapping voices, while preserving some basic and essential rules of harmony. Forms such as sonatas and concertos were also structured by clear rules.