Computer-Assisted Music Creation using AutoHarp: GENERATION 1

This whitepaper explores a process of creating music, specifically short (3 to 4 minute) pop songs, using an algorithmic music generation software package called AutoHarp. It details the process of creating The Inquisitivists' first musical release, the three-song Lost on this Island e.p., which will be linked here for download when it is available. Additional sound and data files generated by the program are embedded below as well. This is "Generation 1" of a long-term art and science project exploring the nature of creativity and machine intelligence. We expect this process to evolve and change as AutoHarp becomes more advanced, and as the field of machine creativity evolves in general. In this iteration, a human was heavily involved (e.g. as lyricist, singer, and producer). As the technology improves, we expect that involvement to change; indeed, the changing relationship between man and machine is the theme that drives the art created by this project.
AutoHarp is a suite of algorithmic music generation tools created by the author, currently in active development (c.f. other whitepapers concerning machine learning and neural networks on this site). The version that was used to create the songs on the Lost on this Island e.p. is documented and available for download as the mainline branch of this project on GitHub. It outputs music in the form of multitrack MIDI files (using MIDI format 1), with appropriate MIDI patches selected and assigned to each track (a bass patch for the bass part, pianos, organs, or strings for the rhythm instrument, drums for percussion, etc).
Of the three songs on the e.p., two were generated via an iterative process described below. The third, "Falling for the World," was created by taking the following 8 bars that were generated by AutoHarp

and looping them, via cut and paste, in a digital audio workstation (Apple's Logic). For this composition in particular, the 8 bars above were the extent of the machine's tangible contribution to the song. From an artistic point of view (and probably also a legal one), this isn't true: it is recognizably the crux of the final song, and the song's lyrics tell the story of art generated by a machine. It is both foundation and inspiration. The debate of the machine's true role in creating this song, while absolutely within the purview of the project, is, however, outside the scope of this paper.
The other two songs were created via the process that follows. Their foundational MIDI files were generated (along with somewhere between 250 and 500 others) to create an album for the 2015 RPM Challenge, an event in which the author regularly participates (click the link for more information). The author ran AutoHarp's "generate" utility (which creates a new song and outputs a MIDI and a data file) over and over again, listening to each composition for as long as it held his interest, marking ones that were notable to him in some way and passing over or deleting ones that he deemed unworthy. This relationship was very like a music producer with access to a composer who wrote new music for the asking, never grew tired, and was never offended when the producer rejected its songs. Here are some example snippets of generated pieces that were saved, but for one reason or another were not developed any further:

From this process, the pool was winnowed down to a handful of songs (completing the RPM Challenge requires ten songs, the author selected 12 at this point) which were workshopped. As a human song writer will take a song that has a solid musical foundation and rewrite the bridge, repeat the chorus after the second verse, or add a prechorus, AutoHarp can do the same via the "regenerate" utility. The "generate" utility produces a data file along with the MIDI; "regenerate" takes that file as input and creates a new song. Deleting elements out of the file before feeding it back in causes AutoHarp to regenerate those parts, and changing chords or melodies manually causes AutoHarp to use those instead. "This Cosmic Place," which appears on the e.p., is the only song of the 12 that didn't go through this process--its structure, progression, and instrumentation remain as the machine originally wrote it (Thief of the Daylight, by contrast, went through 10 different bridges before the author "suggested" his own set of chord changes and a new song structure with the bridge played twice, and had AutoHarp iterate on that structure).
At this point the resulting MIDI files were imported into Logic and assigned more fully rendered instrument patches (either built in to Logic or from third parties). At this point the machine's job was done--it had composed and played what it was going to play. The author wrote lyrics, sang them, and added guitar parts. Some extremely game musicians known to the author added additional vocals and guitar (thank you Jennie and Andy). This is also the stage at which the author, as a music producer might, went in to tweak individual notes. An example of that from "Thief of the Daylight" appears below:

(AutoHarp output)
(same section, produced)

Note how the machine's clav track repeats the same motif every measure, whereas the produced version has had its last four notes altered slightly on the second and fourth measures of the phrase.
After completing the RPM Challenge, the author did some polishing and then went and solicited some musical opinions to determine what should be on the final release (thanks everyone, you know who you are) some of whom knew the nature of the project and some of whom didn't. The result is the three songs that appear on the e.p. We hope you enjoy it and feel inspired to evangelize it a little. Links to the original MIDI files for each of the three songs, and final AutoHarp data files that will generate them appear below.

• Falling for the World: MIDI, JSON
• Thief of the Daylight: MIDI, JSON
• This Cosmic Place: MIDI, JSON