Karlheinz Essl

This Max library offers the possibility to experiment with a number of compositional techniques, such as serial procedures, permutations and controlled randomness. Most of these objects are geared towards straightforward processing of data. By using these specialized objects together in a patch, programming becomes much more clear and easy. Many functions that are often useful in algorithmic composition are provided with this library - therefore the composer could concentrate rather on the composition than the programming aspects.

The Real Time Composition Library (RTC-lib) was developed during my extensive work on Lexikon-Sonate (1992 ff.), an interactive realtime composition for computer-controlled piano.

Regardless the fact that it was conceived for a specific project it became more and more obvious that its functionalities are open and generic enough to be used by other composers in different compositional contexts. Based on paradigms which have been extracted from serial thinking (cf. Gottfried Michael Koenig and Karlheinz Stockhausen) and its further development until nowadays it does not force towards a certain aesthetic, but provides a programming environment for testing and developing compositional strategies.

The Real Time Composition Library comes with a Hypertext-like on-line help which allows to have a perfect overview on the library objects and their multiple relationships.

Released: March 19th, 2014. Suitable for Max5, Max6, and Max7.

rtc-lib-real-time-composition-library-6-0-1

I think the path to install files is not correct anymore with Max 7, is it possible to update it?

Hi, i'm a Windows user. Is there any source files for the externals so i can try a port to Windows?

the abstractions will then work right away.

Hi, i'm a Windows user. Is there any source files for the externals so i can try a port to Windows?
the abstractions will then work right away.
many thanks


awesome that you are still updating this after years! +1 for windows externals or source.

awesome that you are still updating this after years!   +1 for windows externals or source.


I just released version 7.0 which is optimized for Max7, but also runs smoothly with Max6. This time, the library is distributed as a package (hi, Sergio!). You can download it from 

I just released version 7.0 which is optimized for Max7, but also runs smoothly with Max6. This time, the library is distributed as a package (hi, Sergio!). You can download it from http://www.essl.at/works/rtc.html


Thanks for offering this, Alfonso! Unfortunately, I don't have the source code of the Windows externals, but here is a link to Peter Elsea's (the author of Lobjects) who already ported them to Windows XP:

Unfortunately seems that Peter Elseas's Lobjects are compiled only for 32bit Max on Windows.

Are Lobjects the only custom externals used in your library?

Is there any way to get in touch with Peter to ask him for sources to be compiled for Win 64bit?

Thanks for the info Karlheinz!
Unfortunately seems that Peter Elseas's Lobjects are compiled only for 32bit Max on Windows.
Are Lobjects the only custom externals used in your library?
Is there any way to get in touch with Peter to ask him for sources to be compiled for Win 64bit?

Alfonso, please send me an e-mail at khz@essl.at so that I can connect you with Peter Elsea!

Any progress with the 64bit versions of Peters objects?

There is a beta version on Peter's website: 

There is a beta version on Peter's website: http://peterelsea.com/lobjects.html


Thanks but I'm confused. I was talking about win 64 version but he released some 64 bit files for mac. As far as i know there's no need to build separate 64 bit versions for mac externals.

RTC-lib (Real Time Composition Library) 6.0.1