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Scheme For Max - v0.3 (Nov 2021)

Scheme For Max (s4m) is an open source Max/MSP external to enable scripting, live coding, and algorithmic music in Max/MSP with s7 Scheme Lisp. It is available as a packages for Mac (Intel and M1) and Windows (32 and 64 bit), and as source. It has been developed and tested on Max 8. It also works in Max for Live on Ableton Live 10 and 11.

Recent News

2022-07-28: There is now an official forum thanks to the Discourse community program.

2022-02-22: There is now a Universal Binary build for Apple Silicon up for 0.3. This is a drop in replacement for the external object and should work on M1 and Intel Macs.

2021-11-27: 0.3.0 is released. This includes convenience features like directly passing code messages to the s4m object, a threading macro similar to Clojure and Rackets, supporting delay from the low-priority thread, garbage collector interface functions, and tools for using the Ableton Live API from Max4Live. Please report any bugs as github issues. Note: This has not been built for Apple Silicon yet. If you are able to help do this, please get in touch.

2021-04-20: I've put up an e-book tutorial on writing sequencers, along with sample code and patchers in the Scheme for Max Sequencing toolkit here:

2021-03-15: I have released a free e-book on learning S7 Scheme and Scheme For Max, suitable for new and experienced programmers!

Main Documentation lives here:

Demos and Tutorial videos on YouTube Music With Lisp channel:


Scheme-For-Max provides two objects: s4m (the interpreter, formerly named s4m.scm) and s4m.repl (a REPL GUI patcher)

Features of v0.3 include:

  • Hot reloading of scheme code
  • A built in REPL terminal editor for interactive coding
  • Max messages on inlet 0 automatically execute as Scheme code
  • Dynamically registered listener functions for Max messages on inlets 1+
  • Sending messages to remote objects by scripting name
  • Ability to run in either the high or low priority thread
  • Table access and i/o
  • Buffer access and i/o
  • Dictionary access and i/o, including nested lookup
  • Integration with the Max transport controls
  • High-accuracy event and function scheduling
  • Support for Max time notation for scheduling
  • Quantization with master transport settings
  • Live API support in Max4Live
  • garbage collection functions and heap-size control for performance

Scheme-for-Max uses S7 Scheme, a "lisp-y" embeddable Scheme implementation by Bill Schottstaedt at CCRMA, based originally on Tiny Scheme. S7 is a minimal Scheme, with many nice features for algorithmic composition and embedding, and is the Scheme engine used in the Common Music algorithmic composition toolkit and the Snd editors from CCRMA. It has keywords, Common Lisp style macros, first-class environments, thread safety, applicative syntax, and a very straight forward FFI (foreign function interface). Linguistically, it is mostly R4RS with some later extensions, and is quite similar to Guile. It shares many features with Clojure as well, and is easy to learn for anyone with Lisp experience.


Video demos are available on the Music With Lisp youtube channel here: The overview ( is a good place to start.

There is also a small cookbook with some examples available here:

Support Development

If you enjoy Scheme for Max, please consider supporting development on my patreon account. Every bit helps me spend more time on Lisp music projects and less on regular work! There are no real perks though, all Scheme For Max releases, docs, and examples are free for everyone.

Releases and Installation

Binary packages are available for OSX and Windows: Download the Scheme-For-Max tar file and untar it in your Max Packages directory. The Package manager should detect the Scheme For Max package and enable you to launch the help patcher. Note: if you get errors with the s4m object not being found, double check that the external files are actually in the externals directory. Some users have reported issues where security software quarantined or blocked these files on a seemingly successful install. The external should be s4m.mxo on Mac, or s4m.mxe and s4m.mxe64 on windows.

Currently tested on Max 8, on Mac up to Monterey (Intel and M1) and Windows 10. Please report problems installing to the google group, as well as any fixes or workarounds that could be added here.

The current "production beta" is 0.3.0. Subsequent releases should be considered experimental for testing.

Installing on Mac OSX Big Sur

As above, move the Scheme-For-Max folder into ~/Documents/Max 8/Packages. Open the externals folder, hold down the control key and right click s4m.mxo and choose "open". You'll get an ugly warning about not being able to veify it's not malware. Finally click on the "open" button. Nothing will really happenm but now scheme for Max should be usable.

Installing on M1

As above, but replace the s4m.mxo file with the one in the Universal Binary update for 0.3. This is temporary during testing.

Documentation and Community

An extensive help file demonstrating all official features of the release is included, with sample source code in the package. Clicking "launch" on the package menu will open this file.

Narative documentation is here:

The online community lives here:

Learn S7 Scheme and Scheme For Max E-book:

Tutorials on sequencing with Scheme For Max:

To file bug reports or fork Scheme For Max, use the github repo:

To file tickets about errors or improvement suggestions for the docs, use the docs repo:

The S7 reference document is here:

For release and tutorial announcements, questions, suggestions, installation issues, and bug reports, please join the scheme-for-max forum or google group and check the discussion board on this github page.!forum/scheme-for-max

Building from Source

You will need the Max SDK and some understanding of how to build Max externals. The S7 sources are included here. Details on building from source are in the narrative docs here


As s7 Scheme, and TinyScheme on which it is based, are BSD licensed, this is too.