ABC is a tune notation format. It's mostly intended for modern, Western music, i.e. 12 semitones/octave, bars, time-signatures, etc. It's used quite widely in the folk music world. It uses source files that are human-readable and platform-independent, so they can be edited with any text editor and exchanged via email. There are lots of systems available to typeset tunes, play tunes through speakers or to an audio file, manage tune collections, etc. Chris Walshaw's abc page is a good place to start, with an explanation of the format and links to software and tune collections.
Many of the Monday Musicians sheets were typeset using ABC, so where possible we've provided the ABC source in the archive in case it's useful. However, please note that:
- We've provided source for individual tunes rather than attempting to provide source for complete sheets ... except that in some cases a tune and its countermelody are together in a single ABC file.
- When these ABC files were written they weren't intended for distribution, and some of them were written by software packages rather than a human. This means that sometimes they may not be very clearly laid-out, and some may contain some package-specific material.
- Occasionally the ABC source may not quite match the typeset sheet. For example, someone may have changed a chord in their ABC version of a tune between typesetting it and putting the ABC file in the archive.
- Many sheets were typeset in various other ways so we don't have ABC source for the tunes at all.