Slicer is a sound app by
version alpha 0.2 - Dec 2014.

Download page :

Latest unstable versions of source code can be downloaded at your own risk from

Contents of documentation:
- Description
- License
- System requirements
- Mailing list
- Installation
- Short tutorial / how to
- Changes
- To do
- Aknowledgements
- Troubleshooting
- Feedback


Slicer allows you to create rhythms and textures from any sound file you import by moving the Slicer nodes. Slicer will chop your sound into slices and superpose them. The slices will be created and manipulated according to the position of the control nodes (the ones represented by a square). The slicer nodes (in color) control volume (vertical) and pan (horizontal) of each slice, while the control nodes control pitch, length, shift and starting point for all the slices.

A Slicer demo video is available at

Slicer has been constructed using Mirra, a Python 2D OpenGL graphics library developed by ixi. It can be downloaded from Find more detailed info on Mirra check


License :

This application is free software; you can redistribute it and/or modify it under the terms of the GNU, General Public License as published by the Free Software Foundation.

This application is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with this library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

Slicer contains parts and libraries by others such as Mirra (LGPL), python, pygame (GPL), pyopengl (BSD), and wxpython (wxWindows Library Licence).

Pyo (GNU GPL v3).


System requirements:

Slicer works under OS X, Windows and GNU/Linux.
The development has been done under GNU/Linux and even we test it under Windows and OSX we encourage you to report problems you might encounter under windows and OSX. We test our apps in all platforms but probably not as in depth as you when you are using them!.

Slicer should run ok on a 1100mhz PIII laptop with 258 RAM and 16M graphics card both under XP and GNU/Linux, but you might want to use a better graphics card for less CPU load.

If you run Slicer from the python source you need the following dependencies
python, mirra, pygame, pyopengl, wxpython, Pyo



Uncompress the zip, move the Slicer to any directory in your machine and just run it.

Please report errors or bugs to info AT



- fixed many errors related to paths and multiplatform and audio engine

0.1.6 :
- new sound engine based on python pyo - sessions and prefs are now json files - hundreds of other tweaks

0.1.6 :
- added wind control circle
- CTRL+Click on a node resets its movement direction
- keyboard shortcuts added
- fixed several small bugs related to session open/save

0.1.5 :
- added save/open session functionality
- added box control speed pannel
- upgraded to python 2.5 and pyOpenGL3 on windows version
- on mac the sound folder moved out of the package

0.1.2 :
- added lock nodes entries in General menu
- added basic open and save functionality in File menu
- added random situation of boxes and nodes independently in Auto menu
- some optimisation in the render process with call lists and glRect

0.1.1 :
- fixed ReleaseMouse problems
- optimised performance bypassing mirra render methods to expose OpenGL on Slicer render methods
- mac included latest standalone scsynth UB compiled by
- mac removed supercollider classes folder, it was not needed.
- prefs.txt moved one level up from data folder

0.1 :
- switched to Python for graphics and SCsynth for the sound engine.


Short tutorial / how to:

Note that this is a quick description of the Slicer's features, you are welcome to write something more in depth and sent it to us to include here!

- Controls :
Vertical and horizontal position of control nodes (the bigger squares) change pitch, start point, slice length and start point shift.
Slice boxes (in color, surrounded by a circle) control pan and amplitude for each of the slices.
Layers (in the background) show the chuck of the original sound that each slice is playing. Layers and slice boxes are associated, Layer number 0 and slice box number 0 represent sound slice number 0, they have same color and are labelled with the same number. Mute/unmute each slice by right clicking on the slice box or in the layer associated to it. If mute the slice box will be labelled as 'Muted' and its Layer display will fade away. The numbers in the left side of the layers display the start and end point of its sound slice, this is currently display as numbers ranging 0 to 1. Soon it will be displayed in milliseconds. We will also draw the shape of the sound in each layer.

- Sounds :
Slicer will automatically try to load all sounds in the "sounds" folder at start up into the sound pool. This means that they are loaded in RAM and accessible for use. You can add more sounds or folders with sounds from the sound pool menu.
Several file formats are compatible; wav, aiff, ogg ... both mono and stereo - Preferences :
There is a file called prefs.txt next to the application where you can change your startup preferences. BEWARE that if you break the file formatting this might not be read properly by Slicer.

- Menu File > Save / Open sessions :
Slicer allows now to save/open sessions. A session is just a text file that saves the details of the system in a specific moment . By opening old files we can go back to previous situations. To make sure the sounds are found by copying them to /sounds folder before importing to Slicer.

- Pitch control panel :
This panel allows to set the top, central and bottom values for the pitch range. It allows to choose which pitch range we want to work with in Slicer. You MUST press the update values button for the new values to de updated. Setting Microtones option off will force the pitch transformation to be in tone steps.

- Auto menu : Box auto movement panel allow to set the speed of the box movement. This will change pan and volume for each slicer according to the wandering of the boxes With node auto movement on, control nodes will do small jumps randomly. To stop them set speed to zero.



- loop crossing control
- bounce/wrap box movement on window limits
- click dest point and asign it to box
- flock behaviour add with pannel to control strenghts
- hold playhead
- reset > make it work properly
- reset to mouse locH?
- nodes jump back to prev position after dragged with mod key pressed
- half a tone steps when microtones is off
- draw wave on graph display -> enable/disable on menus
- record path of boxes
- move selected boxes with arrow keys and shift and from GAMEPAD
- display shift/st point etc.. in millisecs
- freeze sound loop like with old app
- one parameter effect for individual layers that can be controlled from the ring
- envelope in the display?
- grid showing pitch add 1, -1 lines to display

panel / menus:
- help menu opens documentation on browser
- plot wave out on panel like PD table
- plot sound output spectrum
- wxpannel with output general effects or filters (dist, delay, tremolo, lbp,hp, eq...)
- On/Off microtones, audio, pitch, pan, amplitude slider * its all already on the menus, not sure if it is useful to have it here as well
- out equalicer ?
- gamepad mapping configuration panel
# - file menu open/save/saveas to save configuration
- fixed color gradient for display?
- something like PD's wvvw external to select which part from the sound goes into the app?
- rec to disk
wx to do :
drag n drop on window?

mirra to do:
setMouseVisible in wxpython
email us with your request or ideas to info AT


Aknowledgements :

Some parts of the development of and Slicer Mirra were developed with the support from different institutions :
- The Digital Research Unit at the University of Huddersfield.
- The Lansdown Center for Electronic Arts at Middlesex University who helped providing expertise and support for developing the early versions of Mirra.
- Bizkaiko Diputazioa, Basque Country.
- Buchsenhausen Kunstlerhaus, Innsbruck, Austria.

thanks to patrick, tom schoulten and tom betts for the technical help.

Troubleshooting :

"I get clicks sometimes" :
some sounds click when crossing the loop point, this is in the to do list ... please be patient.

Any other kind of errors :
Under windows and mac in case of errors the application leaves a log file called "slicer.log" or "slicer.exe.log where the errors are described, copy the text and send it to us in an email. Please include as much info as possible about the error and your system (OS version, soundcard, processor speed), we will try to help. On Linux just copy the error from the console.


Feedback :

We would more than happy to hear your comments, suggestions or to incorporte any improvement you might do to our code. Contact us on
If you have some music you have produced using Slider we would like to hear it. We keep links to ixi user's music in our Label section.