BEK 24.05.2005 11.0028.05.2005 16.00


The workshop component is a four day overview of Pure Data, GEM and PDP, a collection of Free + Open Source Softwares available for Linux and Mac OSX 10.3 which allow image, sound and data to be synthesized and manipulated in the same environment. Participants will learn the basic “grammar” and “vocabulary” of Pure Data, upon which objects for sound, 3D and video will be added. Emphasis will be placed on direct connections between sound and image through three different methods: influence of sound on image, influence of image on sound and the use of common “control data” for both image and sound

Workshop details:

Day one

1) Introduction: Why PD & Why Free + Open Source Software?

Our decision to use Pure Data has been motivated by several factors. First and foremost is the need for a modular environment where audio and video processing is possible without the intrusion of negative elements such as a predetermined Graphical User Environment, cross-platform issues and restrictive licenses. We will discuss these issues, and why it is more important than ever that artists take Free + Open Source Software seriously as tools for creative expression.

2) Installation Clinic

The first part of the workshop will be devoted to installing Pure Data, GEM, PDP and several other externals on the participants’ computers. Mac OSX 10.3 and most Linux distributions can be accomodated. While PD and GEM support Windows, PDP and several other externals do not, so Windows users will be encouraged to use a live Linux CD such as Dynebolic during the workshop. (BEK will provide some Linux and OSX machines for those who don’t bring their own laptops).

3) Pure Data as a Language

Like learning any new language, PD starts with learning vocabulary and grammer. In this case, we will learn the names of many common objects
and the syntax of how to use them, in a clear “Geek-to-English” translation which makes the complex data-flow operations of PD understandable to non-technicians and artists.

4) Pure Data for Sound Synthesis

PD has powerful signal-processing abilities, and we will explore these by building a simple, monophonic synthesizer controllable from either a MIDI device or from the keyboard of your computer. Different types of sound sythesis, such as Additive, Subtractive, Amplitude Modulation, Frequency Modulation and Wavetable Synthesis will be covered, along with the use of filters and delays for a variety of effects.

Day two

1) Pure Data for Sample Manipulation

Because PD uses a range of very basic building-blocks to store and playback sampled sound, a wide range of manipulations are possible. Here, we will explore pitchshifting, time stretching, looping and basic granular synthesis. Other uses of data stored in tables for control purposes will also be touched on.

2) Pure Data for 3D: GEM

GEM is an external library used in PD for moving 3D graphics under the OpenGL protocol. It is also an ideal environment for VJ mixing. We will explore how to create and manipulate simple 3D objects, how to texture them with images, how to playback and mix video clips in GEM and how to use a live camera input.

3) Pure Data for Physical Modelling: PMPD

PMPD is an external library for PD which allows the creation of physical models, consisting of units of mass and force, which can be used to control both sound and image. We will look at different examples of physical modelling using the sound-processing of PD as well as 3D graphics from GEM to sonify and visualize our “virtual objects”.

Day three

1) Pure Data for Audio Analysis

We continue our investigation of the audio side of Pure Data by looking at different methods of analyzing sound signals for pitch and amplitude information. The data we extract from the audio can be used to either (re)synthesize new sounds or to control 3D or video graphics manipulations.

2) Pure Data for Video: PDP

PDP (Pure Data Packet) is another external library in PD which is used primarily for video playback and effects filters. We will investigate PDP for direct video synthesis, for the playback and mixing of (audio)visual clips and for the processing of a live camera input. PDP includes several tools for the analysis of video for movement, change and color, which in turn can be used to control sound playback and other events in PD.

Day four

1) Pure Practical Examples

Now that the workshop participants have the background to understand more complex PD patches, we will spend the morning looking at various demos and performance patches to see how different artists and programmers have developed their own environments for live audiovisual synthesis.

2) Pure Data Practice

Workshop participants will put what they have learned into practice by working in small groups, pairing sound artists together with video artists to create simple audiovisual performance tools, with an emphasis on the interrelation of sound and image.

Day five

1) Workshop Presentation

Public presentation by instructors and workshop participants of tools created during the week, covering the importance of Free + Open Source Software, as well as the practical examples of its use.


  • Nicholas Ward
  • Bertrand
  • Mona Bentzen
  • Lisbeth Nordli
  • Terje Urnes
  • Beate Fossbakk Birketvedt
  • Nina Svane-Mikkelsen
  • Eirik Olsnes