What is RTcmix?

RTcmix is a real-time software "language" for doing digital sound synthesis and signal-processing. It is written in C/C++, and is distributed open-source, free of charge. In certain respects, it is similar in function to other extant unit-generator-based software languages such as CSOUND, SuperCollider and (to a lesser extent) JSyn and Max/MSP -- they do share a common heritage, after all. There are some differences, however, between all these languages... and variety is of course the spice of life!

So if you've been searching the web high and low for just the right library of DSP functions to include in your latest&greatest "killer" (or maybe "peacefully coexisting"?) app, then RTcmix may just be the Right Package for You.

RTcmix currently includes the following components:

• a library of low-level C/C++ functions and objects for performing most contemporary digital audio and signal-processing tasks
  
• a substantial set of pre-coded "instruments" instantiating a variety of DSP and sound-synthesis algorithms (click here for a list)
  
• a fully-featured command-parsing langauge to allow easy incorporation of algorthmic control procedures in sound generation
  
• an option to allow the perl or python programming languages to be used as the control/command-parsing environment for RTcmix
  
• a robust and sample-accurate scheduler for timing and arbitrary event-scheduling
  
• an 'imbedded' RTcmix object and associated library to enable the entire RTcmix language (scheduler too!) to be compiled and used seamlessly within other C/C++ applications
  
• a TCP/IP socket interface for external control of RTcmix from other processes or machines
  
• the physical model and PhISEM routines from Perry Cook and Gary Scavone's Synthesis ToolKit (STK) as well as affiliated RTcmix instruments using the stk routines
  
• the ability to read/write most contemporary soundfile formats by via Bill Schottstaedt's sndlib
  
• a package of examples showing RTcmix use with MIDI, X11/motif, wxWindows, Lisp, Open Sound Control (OSC), OpenGL, etc.
  
• a set of command-line utility programs for playing and manipulating soundfiles
  
  recently completed:
  
• a Max/MSP rtcmix~ object
  
• VST plugin authoring capability (via max/msp "pluggo")
  
  coming soon:
  
• VST plugin authoring capability (we hope!)
  
• dynamic p-field modification
  
• "pull"-model for audio i/o (JACK, PortAudio, etc.)

RTcmix compiles and runs on most Unix-like systems, including various flavors of Linux, Mac OSX, IRIX, FreeBSD. A windows port is currently being developed by students of Akira Takaoka at the Tokyo University of Technology.

The Ancient History of RTcmix

Luke Dubois wrote a brief history of RTcmix back in the mid-1990's, quoting from an earlier brief history of CMIX written by Brad Garton (me!). The histories are in fact still historical, but a few recent (c. 2000-2003) RTcmix events worth noting -- if you are the kind that likes noting these things.

With the demise of SGI machines as a semi-platform-of-choice for the computer music community, RTcmix went into a period of 'underground' usage. As noted in Luke's document, it was ported to Linux and was further developed by a core group of RTcmix users who also adopted Linux for musical work. Dave Topper and John Gibson at the University of Virginia (John is presently at Indiana University) and Doug Scott (formerly of SGI, now with Beatnik) in particular added extensive new features to the language and greatly expanded RTcmix capabilities -- perl/python interface, instrument interconnecting ability, much larger instrument base, etc.

But by and large, not too many new users began working with RTcmix, primarily because we never took the time to create a coherent body of documentation. Luke, followed with additional work by Dave and John, added to the tiny existing RTcmix documentation (and much of their work has been incorporated into these web pages), but to use RTcmix you sort-of had to know how to use it already.

I was still using RTcmix a fair amount in my own musical work, but I also began to look at other languages (like JSyn, Max/MSP and SuperCollider). One of the things I didn't like about these languages was the difficulty in incorporating them into C/C++ applications with a high degree of data-sharing. I also rediscovered how much I enjoy the straightforward algorthmic processing capabilities of RTcmix. So, with help from Doug/Dave/John, I wrote an 'imbedded' RTcmix object to facilitate the C/C++ connection, and decided to get our documentation house in order so that others who might want a language like RTcmix could gain entry.

That's the story so far. With a solid Linux version and an equally solid port to Mac OSX (and rumors of a Windows version soon), we believe RTcmix may again be attractive for other programmers-musicians-audio people. Please browse through the documentation here (especially the tutorials), download and try a few instruments, join the RTcmix mailing list, etc.

We hope you find the language useful!


Brad Garton
August, 2003