This month, March 2015, marks J.S.Bachs 330th birthday. For the occasion, the Pirate-Fugues team has published a new edition of 4-voiced transcriptions of the songs from Schemellis Musicalisches Gesang-Buch, BWV 439–507. LilyPond is among the tools in our production pipeline.
Some of the arias in Georg Christian Schemellis song book are fairly well known, for instance: Ich steh an deiner Krippe hier, BWV 469, and Komm süsser Tod, BWV 478.
Each original score from the collection consists of 2 voices:
- a soprano voice with lyrics, and
- a bass voice with Generalbass notation.
Here is an example: The first few measures of Mein Jesu, was für Seelenweh, BWV 487
In order to create a 4-voiced transcription, we add 2 voices in between the 2 existing ones. The resulting score could look something like
Transcriptions of these songs already exist. So what is special about our edition? Our goal was to create the 4-voiced transcriptions as faithful as possible to J.S.Bach’s own musical style. And, we want the computer to help us do it. Our composition approach is data-driven: Our custom made software harvests patterns from over 1700+ digitized scores by J.S.Bach.
The process is not fully automated, and we don’t think this is desirable anyways. Instead, the software computes between 10–30000 suggestions of up to 3 measures in duration. The suggestions are readily sorted according to intuitive mathematical criteria such as
- voice coverage,
- number of notes,
- frequency of note constellations in database.
These and other categories allow the user to filter and narrow down the numerous possible insertions in a convenient and meaningful way.
The creative process usually takes 15–45 minutes for an entire song and requires a lot of user interaction. The video is only a summary to illustrate what the computed suggestions look like for the song BWV 487 already introduced above:
Note that, the sequential start-to-finish fashion is only to make the video align with the music. During the composition phase, the user can choose to edit the score in any order.
Before we elaborate on the role of LilyPond in our publication, we wrap up the description of the project:
Our software has a unique set of requirements:
- the music notation (as shown in the video) requires precise control over the note placement in order to prevent jerkiness when browsing the suggestions;
- extra information is drawn into the score: selected pitch range for computation, available pitches in the suggestions;
- user interaction with the mouse filters and narrows down the suggestions.
No prior API was available to perform these tasks. So instead, we developed our own and called it The Pirate Fugues.
The audio for the collection of 69 songs is synthesized using 3rd party software Pianoteq, Ivory II, and Hauptwerk (all trademarked!, and to none of which we are affiliated). For each song, we provide an animation that visualizes the suggestions by our software and indicate the local correlation of the final score to the database. The website of our project is http://djtascha.de/schemellis-gesangbuch/ where you can listen to the results, download the sheet music, and find additional information on the technique.
Disclaimer: Faithful to J.S.Bach’s style is a bold claim and one that invariably sparks controversy. Although we have taken great care in compiling each score in the collection, there is room for improvement. Apart from creating the music, another objective of the project was to learn about the strengths and weaknesses of the software. Independent of your background in music, feel free to let us know what you think. Thank you!
Now, back to LilyPond:
We have introduced LilyPond to our workflow about 2 years ago. From Lilypond, we have adapted
- the chord notation,
- the ornament labelling and graphics, as well as
- the Mensur note apparel.
Since then, all scores from our projects are algorithmically exported LilyPond for on-screen preview, and ready-to-print pdfs. We are not aware of any alternative to LilyPond that is as convenient and yields results of the same visual quality.
In the future, we hope that notation software like LilyPond will be able to imitate the handwriting of famous composers such as J.S.Bach.