The SndObj Sound Object
Library Page

Welcome to the Sound Object Library resource page. Here you you will find everything about the SndObj Library: source code, documentation, programs, etc.. As usual, you can send me an e-mail with any comments you wish to make. My e-mail address is

The Library

The Sound Object Library is an object-oriented audio processing library. It provides objects for synthesis and processing of sound that can be used to build applications for computer-generated music. The core code, including soundfile and text input/output, is fully portable across several platforms. Platform-specific code includes realtime audio IO and MIDI input support for Linux (OSS,ALSA and Jack), Windows (MME and ASIO), MacOS X (CoreAudio, but no MIDI at moment), Silicon Graphics (Irix) machines and any Open Sound System-supported UNIX. The source code for the core library classes can be compiled under any C++ compiler.

The library & accompanying programs are Free software, licensed by the Gnu Public License

The SndObj library was nominated Linux/Open Sound System Killer App of the month (June/2000) by the OSS people at 4Front Technologies.

The library documentation is distributed separately in portable document format. A discussion list, is also hosted by sourceforge. If you have a general query, you are welcome to join the sndobj-devel list or to look at its archives .


Please go to the downloads page.

Building instructions

  1. Building sources with scons:

    1. You will need scons ( and python ( Most linux systems will have these already; OSX 10.3 and later will only need scons, as python is in the system.

    2. Fire up a terminal (or a command prompt) and run 'scons' from the top-level directory

    3. For standard build options try 'scons -H'; for SndObj-related options try 'scons -h'

  2. Building with MSVC: a MSVC project file is found under ./msvc6.0

      Big thanks to Tim Blechmann for the original SConstruct code for the SndObj library


The complete reference manual is now available as PDF from the project downloads page. This contains the reference for all library classes in the current version (2.6.2).

The documentation is in process of expansion. New documents will be available on different aspects of SndObj programming.

C++ Programming

A number of C++ example programs are bundled with the library. You can check their source code in the examples page.

Python Programming

The SndObj library also exists as python module. The programming principles are similar to the C++ use of the library. It is also possible to use the python interpreter for on-the-fly synthesis programming. The python module is created using swig, and has been added to the sources in version 2.6.3 (currently at beta stage, but can be accessed via cvs on As a quick example (more to be added to the documentation), here's a simple python script implementing an amplitude-modulated instrument:

import sndobj
import time

tab = sndobj.HarmTable()
osc = sndobj.Oscili(tab, 10000, 440)
mod = sndobj.Oscili(tab, 44, 2)
outp = sndobj.SndRTIO(1, sndobj.SND_OUPUT)

osc.SetFreq(440, mod)
outp.SetOutput(1, osc)

thread = sndobj.SndThread()
thread.AddObj(outp, sndobj.SNDIO_OUT)


Other Languages

The SndObj library has bindings for Java and CFFI (developed by Todd Ingalls), allowing it to be used under those languages, in a similar manner to PySndObj.

PD development

A new wrapper, developed by Thomas Grill from his flext is now available. This enables the quick development of PD classes using SndObj library objects.
For more info, see the obligatory C++ layer for PD and MaxMSP objects on

and a first version of the sndobj interface (with a trivial example)

Simple PD classes can also be coded directly with the SndObj library. A simple example is provided with the distribution (in /src/examples).

LADSPA development

The SndObj library can be used for LADSPA (Linux Audio Developer's Simple Plugin API) plugin development. Such plugins are modelled by the LADSPAplug class, which supports processing by a single SndObj. This class can be used directly or extended for more complex SndObj chains.

A fully-commented code example for a plugin is available. The LADSPAplug class implementation is also found in this site.

LADSPA plugins are dynamic library modules, which can be built with g++ using -shared (and possibly -DPIC -fPIC, but DO NOT USE -nostartfiles) option, similarly to a Linux PD class. For more information on the LADSPA specification and use, see the project website.

VST development

The SndObj library can be used for fast development of plugins for VST 2.0. The VST API is C++-based, so the code integration is very straightforward. Plugins can be developed by using SndObj objects as AudioEffectX class members and issuing calls to SndObj::DoProcess() from the class process/perform methods.

A simple code example for a plugin class and its implementation is available. For more information on the VST 2.0 API, see the Steinberg website