Pupitre D'Espace

Pierre Schaeffer developed the Pupitre D'Espace, a device for spatializing tape music in real time, in 1951. This special case of spatialization for acousmatic music is also referred do as diffusion. The device works with three induction coils for detecting the position of the hand-held transponder in space.

Image from Nicolau Centola's PhD thesis.

Poème électronique

The Philips Pavilion (from medienkunstnetz )

The Philips Pavilion, built for the 1958 World's Fair in Brussels, featured a multi-channel sound system with an unconventional loudspeaker arrangement. It was used for Edgard Varèse's Poème électronique to move sound along paths defined by the loudspeaker positions.

Source movements in 'Poème électronique'

Rotationstisch

Starting in 1959, Stockhausen used a rotating table (Rotationstisch) for creating sound movements in quadraphonic tape compositions. A loudspeaker in the center is rotated with the table, captured by four fixed microphones surrounding it. The directivity but also the inherent Doppler effect creates the image of a rotating sound source, when played back on a quadraphonic setup.

Loudspeaker Orchestras

A loudspeaker orchestra uses loudspeakers themselves as musical instruments, rather than as means for reproducing sound. A typical setup uses models with very different, distinct characteristics, placed at individual positions, rather than in a geometric shape. During a performance, pre-composed music, often stereo, can be sent to the different speakers or speaker groups. This process, referred to as diffusion, is a standard technique in Acousmatic Music.

The Acousmonium

The Acousmonium, launched by French GRM (Groupe de Recherches Musicales) in 1974, is the original and most prominent loudspeaker orchestra.

Francois Bayle with the Acousmonium from "Our Research for Lost Route to Root" (Jérôme Barthélemy, 2008)

BEAST

The BEAST (Birmingham ElectroAcoustic Sound Theatre) is a younger system, following the principles of the Acousmonium. It was brought to Berlin for the 2010 edition of the festival Inventionen, when Jonty Harrison was guest professor at TU Berlin.

The BEAST at Elisabeth-Kirche, Berlin

HaLaPhon

Principle

The HaLaPhon, developed by Hans Peter Haller at SWR in the 70s and 80s, is a device for spatialized performances of mixed music, and live electronics. The first version was a fully analog design, whereas the following ones used analog signal processing with digital control.

The HaLaPhon principle is based on digitally controlled amplifiers (DCA), which are placed between a source signal and loudspeakers. It is thus a channel-based-panning paradigm. Source signals can be tape or microphones:

DCA (called 'Gate') in the HaLaPhon.

---

Each DCA can be used with an individual characteristic curve for different applications:

DCA: Different characteristic curves.

Quadraphonic Rotation

A simple example shows how the DCAs can be used to realize a rotation in a quadraphonic setup:

Circular movement with four speakers.

---

Quadraphonic setup with four DCAs.

Envelopes

The digital process control of the HaLaPhon generates control signals, referred to as envelopes by Haller. Envelopes are generated through LFOs with the following waveforms:

Circular movement with four speakers.

---

Envelopes for each loudspeaker gain are synchronized in the control unit, resulting in movement patterns. These can be stored on the device and triggered by the sound director or by signal analysis:

Quadraphonic setup with four DCAs.

---

References

@incollection{pysiewicz2017instruments,
    author = "Pysiewicz, Andreas and Weinzierl, Stefan",
    title = "Instruments for Spatial Sound Control in Real Time Music Performances. A Review",
    booktitle = "Musical Instruments in the 21st Century",
    publisher = "Springer",
    year = "2017",
    pages = "273--296"
}

@incollection{vonColer2015aspects,
    author = "Brech, Martha and von Coler, Henrik",
    editor = "Brech, Martha and Paland, Ralph",
    title = "Aspects of Space in {Luigi Nono's Prometeo} and the use of the {Halaphon}",
    booktitle = "Compositions for Audible Space",
    publisher = "transctript",
    year = "2015",
    series = "{Music and Sound Culture}",
    pages = "193–204"
}

@inproceedings{vonColer2014thehalaphon,
    author = "Brech, Martha and von Coler, Henrik",
    title = "The {Halaphon} and its Use in {Luigi Nono's 'Prometeo'} in {Venice}",
    booktitle = "{Proceedings of the 9th Conference on Interdisciplinary Musicology ({CIM})}",
    year = "2014",
    location = "Berlin, Germany"
}

@book{haller1995dasexperimentalstudio1,
    author = "Haller, Hans Peter",
    title = "{Das Experimentalstudio der Heinrich-Strobel-Stiftung des Südwestfunks Freiburg 1971-1989: die Erforschung der elektronischen Klangumformung und ihre Geschichte, Teil 1}",
    publisher = "Nomos",
    year = "1995",
    address = "Baden-Baden"
}

@book{haller1995dasexperimentalstudio2,
    author = "Haller, Hans Peter",
    title = "{Das Experimentalstudio der Heinrich-Strobel-Stiftung des Südwestfunks Freiburg 1971-1989: die Erforschung der elektronischen Klangumformung und ihre Geschichte, Teil 2}",
    publisher = "Nomos",
    year = "1995",
    address = "Baden-Baden"
}

Exercise

Where to put SC Classes

SuperCollider classes are defined in .sc files with a specific structure. For compiling a class when booting the interpreter, it needs to be located in a directory which is scanned by SC. For this reason, an installation of SC creates a directory for user-defined content. Inside sclang, this directory can be shown with the following command:

Platform.userExtensionDir

On Linux systems, this is usually:

/home/someusername/.local/share/SuperCollider/Extensions

For more information, read the SC documentation on extensions.

Structure of SC Classes

The following explanations are based on the example in the repository. A class is defined inside brackets, with the class name:

SimpleSynth
{
  ...
}

var dur;

// constructor
*new { | p |
        ^super.new.init(p)
}

// initialize method
init { | p |
        dur    = 1;
}

play
      { | f |
    ...
  }

Creating Help Files

In SC, help files are integrated into the SCIde for quick access. Help files for classes are also created during compilation. They need to be placed in a directory relative to the .sc file with the extension .schelp:

HelpSource/Classes/SimpleSynth.schelp

Read the SC documentation on help files for more information.

TU Website

The official TU website with information on the schedule and assessment:

https://www.ak.tu-berlin.de/menue/lehre/sommersemester_2021/network_systems_for_music_interaction/

Download

The download area features papers, audio files and other materials used for this class. Users need a password to access this area.

Student Wiki

This Wiki can be used for sharing knowledge:

http://teaching-wiki.hvc.berlin

SPRAWL GIT Repository

The repository contains SHELL scripts, SuperCollider code and configuration files for the server and the clients of the SPRAWL system:

https://github.com/anwaldt/SPRAWL

JackTrip GIT Repository

Jacktrip is the open source audio over IP software used in the SPRAWL system:

https://github.com/jacktrip/jacktrip

Back to NSMI Contents

Directories

You can maneuver through the system's directories using the cd command. Changing to an absolute path /foo/bar can be done like this:

$ cd /foo/bar

New directories are created with the mkdir command. For creating a new directory mydir in your recent location, type:

$ mkdir mydir

The content of the recent directory can be listed with the ls command. The following arguments improve the results:

$ ls -lah

drwxrwxr-x  2 username group 4,0K Mar 25 12:25 .
drwxrwxr-x 16 username group 4,0K Mar 25 12:25 ..
-rwxrwxr-x  1 username group 9,1M Feb  3 17:47 jacktrip
-rwxrwxr-x  1 username group 334K Feb  3 17:47 sprawl-compositor

Create and Edit Files

A file can be created by touching it:

$ touch filename

The default editor on most systems is nano. It is a minimal terminal based tool and does not require X forwarding. To edit an existing file or create a new file, type:

$ nano filename

Terminal Only

Inside nano, you have a lot of defined keystrokes for editing, file handling and other tasks. See the nano cheat sheet for a full list: https://www.nano-editor.org/dist/latest/cheatsheet.html

GUI Based

When working with X forwarding, simple text editors with GUI features can be used. On the SPRAWL server, this includes mouspad or the minimal Python IDE idle.

Starting Applications

System wide binaries must be located in a directory that is listed in $PATH (see the final section on this page for details). They can be started by simply typing the name:

$ foo

A local binary named foo can be started with the following command:

$ ./foo

You can terminate your command with an ampersand (&) to run a process in the background. You can continue to work in the terminal, afterwards:

$ ./foo &
[1] 5459

If you start a command this way, it gives you an id of the background process in brackets and the actual process ID (PID).

You can get the process back into foreground with the fg command followed by the background process id:

$ fg 1

Check for Running Applications

At some point, users may want to know whether a process is running or which processes have been started. The command top lets you monitor the system processes with additional information on CPU and memory usage, updated with a fixed interval:

$ top

htop is a slightly polished version, using colored results:

$ htop

You can get a list of all running processes, including auxiliary ones, by typing:

$ ps aux

Usually, these are way to many results. If you want to check whether an instance of a specific program is running, you can use grep after the ps aux to filter the results:

$ ps aux | grep foo

Shell Variables

Sometimes it is convenient to store information in variables for later use. Some common variables that are used in Unix like operating systems like Linux, BSD or MacOS are for example PATH and DISPLAY.

Shell variables are usually uppercase. To get the content of a variable it is prefixed by a dollar sign. The command echo is used to print the content:

$ echo $PATH
/home/username/.local/bin:/home/username/bin:/usr/bin:/bin:/usr/local/sbin:/usr/sbin
$ echo $DISPLAY
:0

Defining a variable is done with an equal sign. It happens quite often that the program that should use the variable, opens another environment. To access the variable in that sub-environment, it has to be exported before:

$ NAME=username
$ echo $NAME
username
$ bash
$ echo $NAME

$ exit
exit
$ export NAME
$ bash
$ echo $NAME
username

JUCE

JUCE is the most widely used framework for developing commercial audio software, such as VST plugins and standalone applications.

JACK

JACK offers a simple API for developing audio software on Linux, Mac and Windows systems.

The Sine Example

The following Web Audio example features a simple sine wave oscillator with frequency control and a mute button:

Sine Example.

Play Stop Frequency

<!doctype html>
<html>

<head>
  <title>Sine Example</title>

  <!-- embedded CSS for slider appearance -------------------------------------->

  <style>
  /* The slider look */
  .minmalslider {
    -webkit-appearance: none;
    appearance: none;
    width: 100%;
    height: 25px;
    background: #d3d3d3;
    outline: none;
  }
  </style>
</head>

<!-- HTML control elements  --------------------------------------------------->

<blockquote style="border: 2px solid #122; padding: 10px; background-color: #ccc;">

  <body>
    <p>Sine Example.</p>
    <p>
      <button onclick="play()">Play</button>
      <button onclick="stop()">Stop</button>
      <span>
        <input  class="minmalslider"  id="pan" type="range" min="10" max="1000" step="1" value="440" oninput="frequency(this.value);">
        Frequency
      </span>
    </p>
  </body>

</blockquote>


<!-- JavaScript for audio processing ------------------------------------------>

  <script>

    var audioContext = new window.AudioContext
    var oscillator = audioContext.createOscillator()
    var gainNode = audioContext.createGain()

    gainNode.gain.value = 0

    oscillator.connect(gainNode)
    gainNode.connect(audioContext.destination)

    oscillator.start(0)

    // callback functions for HTML elements
    function play()
    {
      gainNode.gain.value = 1
    }
    function stop()
    {
      gainNode.gain.value = 0
    }
    function frequency(y)
    {
      oscillator.frequency.value = y
    }

  </script>
</html>

Links and More Examples

https://github.com/mdn/webaudio-examples

OSC Messages

A typical OSC message consists of a path and an arbitrary number of arguments. The following message sends a single floating point value, using the path /synthesizer/volume/:

/synthesizer/volume/ 0.5

The path can be any string with slash-separated sub-strings, as paths in an operating system. OSC receivers can sort the messages according to the path. Parameters can be integers, floats and strings. Unlike MIDI, OSC offers only the transport protocol but does not define a standard for musical parameters. Hence, the paths used for a certain software are completely arbitrary and can be defined by the developers.