Real-Time Corpus-Based Concatenative Synthesis

by Diemo Schwarz, IMTR Team, Ircam--Centre Pompidou, and collaborators.
CataRT is based on FTM&Co. by Norbert Schnell and collaborators.

CataRT comes in three flavours:

See also:



The concatenative real-time sound synthesis system CataRT plays grains from a large corpus of segmented and descriptor-analysed sounds according to proximity to a target position in the descriptor space. This can be seen as a content-based extension to granular synthesis providing direct access to specific sound characteristics.

CataRT is implemented in MaxMSP and takes full advantage of the generalised data structures and arbitrary-rate sound processing facilities of the FTM and Gabor libraries. Segmentation and sound descriptors are loaded from text or SDIF files, or analysed on-the-fly.

CataRT allows to explore the corpus interactively or via a target sequencer, to resynthesise an audio file or live input with the source sounds, or to experiment with expressive speech synthesis and gestural control.

CataRT is explained in more detail in this article and is an interactive implementation of the new concept of Corpus-Based Concatenative Synthesis.


CataRT is offered as free and libre open source software in the spirit of the GNU GPL. All we want is some feedback from you. Or in more details:

  • CataRT is offered for free, so you can make music and create.
  • CataRT is offered as open source software, so you can look into it, learn from it, and adapt it to your needs.
  • CataRT, up to version 0.9.8, is offered under the GNU General Public License (GPL), which means that any modifications you make, or any software that uses CataRT in whole or in parts, must be distributed under the GNU GPL also, so the improvements, variations, adaptations you make will benefit the community of users. (See below for the full license.)
  • CataRT is offered with the wish that you give some feedback if you use it, how you use it, how you would like to use it, what you use it for, or why you don't use it in order to learn from it and to have arguments for Ircam to continue work on CataRT.

The download links send you to the FTM sourceforge project download page which hosts CataRT. (You can choose the download mirror and also activate monitoring of the CataRT package, to be notified of new releases automatically.)

For FTM 2.5 on Max 5 (versions FTM 2.5-beta10 or higher for Max 5.1)

For FTM 2.3 on Max/MSP 4 (versions FTM 2.2.0 or higher for Max 4.6)

  • cataRT-0.9.3 for FTM 2.3.4, 06.03.2008 (unreleased)

For FTM 2.2 (versions FTM 2.2.0 or higher for Max 4.5 or Max 4.6)

For FTM 1.7 (versions FTM 1.7.11 through 1.7.13):


You need Max/MSP 4.5 or 4.6 and the FTM&Co extensions installed which you can download from CataRT runs on Mac OSX and Windows XP (less tested than Mac, so we welcome any experiences) and maybe Vista (completely untested).


  • CataRT is distributed under the GNU General Public License (GPL). Other licenses can be obtained by contacting us, and we'll work something out. The full license comes with the download in file COPYING, and can be read here.


FAQ and examples

  • The CataRT FAQ is hosted on the collaborative FTM wiki, which means that you can add questions and answers (but post them also on the concat mailing list).
  • There's a number of tutorial patches within the distribution.

Articles and Presentations



Mailing List

  • The concat list will receive announcements of news about CataRT and serves for general discussion about concatenative and corpus-based synthesis.

User Reactions

What users say about CataRT:

CataRT is a fascinating tool both conceptually and in the sounds produced.

Ian Blake

J'ai vraiment adoré la simplicité et la beauté de l'idée ainsi que les applications qui pouvaient en découler...
La structuration de données granulaire ouvre des possibilittés inédites et d'une beauté évidente !


Music and installations made with CataRT

Personal tools