JSyn - modular synthesis API for Java.
JMSL - Java Music Specification Language
PortAudio - cross platform audio I/O API for 'C'

HMSL - Hierarchical Music Specification Language

HMSL is a programming language for experimental music composition and performance. It was actively developed between 1986 to 1996. HMSL is an object oriented set of extensions to the Forth language for the Amiga and the Macintosh.

HMSL was created by Phil Burk, Larry Polansky, and David Rosenboom at the Mills College Center for Contemporary Music. It was distributed by Frog Peak Music.

The original distribution is out of print. But the source code is available on GitHub and is being ported to modern day Macintosh and Windows.

Overview of HMSL.

Downloadable examples, fixes, and the HMSL DSP code.

Listen to some pieces

HMSL mailing list, Google group


Oct 30, 2015 - The Whitechapel Gallery in London hosted an exhibit on HMSL curated by Luke Fowler. It contains concert notes, correspondance, documentation, artifacts, videos, and a listening room. The exhibit ran through Feb 7, 2016. See photos here.

Call for Contributions

If you are an HMSL programmer and would like to share your software, writings, or HMSL generated General MIDI files on this web site, please contact us here.