Composers’ Desktop Project – An Old Friend, Now Expanded, and Now Free

The Composers’ Desktop Project began back in the mid-80s with a group of composers at York University, UK. Warren Burt shows us how far it’s come since then.

By Warren Burt, May 2014

Composers’ Desktop Project software (PC or Mac) – (free download)

Soundshaper Pro interface (PC only) – and at (prices start at 20 (student) and 25 (full) GB Pounds (approx. $34 and $42 USD)

The Composers’ Desktop Project began back in the mid-80s with a group of composers at York University, UK, pooling their resources to develop software to run on the Atari computer.  Chief among these were Trevor Wishart, the late Richard Orton, Archer Endrich, Martin Adkins and Richard Dobson.  Later, others would join the team, such as Robert Fraser and Rajmil Fischman.  The chief set of routines in the program, and most of its unique abilities were made by Trevor Wishart.  Over the years the software has migrated to the PC and Mac platforms, and this year, the core programs were made a free download.  This means that there has just been an enormous increase in every computer musician’s capabilities, as many of the routines in the program (such as the “wavecycle” programs) are completely unique to the CDP.

So what is the CDP?  It’s a group of sound processing programs, which natively run in command-line mode.  Its chief focus is on sound modification, and there are over 430 processes available in the program.  Such a sound-tool-box like you wouldn’t believe!  Seeing as how command-line interfaces are clumsy to work with, two interfaces are available for the program: SoundLoom, developed by Trevor Wishart, and SoundShaper, developed by Robert Fraser.  SoundLoom is free, and comes with the program download.  Also included free with the program is SoundShaper Lite, while SoundShaper Pro is very inexpensive and is available separately.  Both interfaces give you access to all the features of the main program, just in slightly different ways, and each has features unique to itself.  Since versions of both come with the free download, if you’re on the PC, you can try them both out and see which suits your working style best.  If you’re on the Mac, then the free SoundLoom is your only choice.

The main focus of the CDP is on sound modification.  It’s not designed mainly to do, for example, sequenced pop music, although it could be used for that, and it can definitely make sounds that would be quite useful in a pop style.  But its main purpose is to take pre-existing sounds, and make sometimes quite subtle and sometimes quite radical changes in them.  In this respect, its a very experimental, or research oriented, suite of programs.  The normal way one uses it is to take a sound, modify it in some way, then listen to the sound, adjust parameters to taste, re-run the modify program, listen to that, etc.  Once one is satisfied with the results of that modification, one can take the modified sound and run it through another program etc.  One can then save a whole sequence of modifications and use them to modify other sounds, etc.  Eventually, you’ll have quite a collection of sounds which you can use in pieces, or put together into pieces, etc.  CDP also has a large number of programs which can assemble sounds, mix them in various ways, and route them in multi-channel space, etc.

The sound modification programs fall into two categories – programs which operate on the waveform of the sound (amplitude changes, filtering, fragmenting, granulating, “wavecycle” modifications) and programs which analyze the sounds and then use analysis as the basis for other kinds of modification (time-stretching, emphasizing, reshaping, removing or emphasizing individual partials, stretching the spectrum, squeezing it, inverting it, etc.)  A complete list of the programs can be found on the CDP website.  A summary can be found at Here’s a summary of the number and kinds of programs included:

 85       EDIT / MIX

 37        ENVELOPE

 18        FILTER

 22        PITCH / FREQUENCY

 19        REVERB / ECHO

 11        EXTEND / SEGMENT

 17        GRAIN


 15        TEXTURE

 12        RHYTHM

 23        DISTORT



 15        MORPH / FORMANTS


 11        SPECTRAL TIME

   6        SPECTRAL UTILS


   9         SYNTH

104        PROCESS DATA

  68         INFO / UTILITIES


And each of these programs has a number of parameters, most of which can have “time-varying” controls applied to them.  For example, the frequency, Q, and gain of a filter can all change over time.  These changes are applied with breakpoint envelopes or text files.  The program provides resources to make both the breakpoints and the text files, or to derive these from another sound.  So it’s quite possible to make sounds which dynamically change over time.  The program also comes with some auxiliary programs, such as Grainmill (granulation of sounds), and Al & Erwin (algorithmic control of sound parameters) which augment the functions.  And the program is continually expanding.  For the latest version, V7, Trevor Wishart came up with 38 new programs, including a very nifty spectrum inverter, and a spectral window randomiser, which scrambles sound in a very unique way.  And there are more programs in the works, as the team develops new capabilities.

Here’s a look at the basic interface for SoundShaper Pro.

The basic functions are in the top part of the window.  The sound file player is in the middle top.  A sound is selected and placed in the Source window at the left in the middle.  It’s then operated on by selecting from the menus at the top.  Here’s a shot of a typical drop down menu to select a process.


In this shot we can see a typical drop down menu.  Here in the Spectral Menu, we’ve gone to the Time window, and we’re selecting Time Stretch.  When we get done with a process, it is stored in the patches window at the bottom of the GUI.  Here we can assemble lists of processes which we can save as patches.


 Now you can see the sound BabbittBells.wav has been selected, and it has been treated with a number of processes.  The list of processes can be saved as a Patch, which can then be reapplied to any other sound.  In this way you can create your own favourite sound modifying instruments.  It’s like having an endless effects-making machine, only a lot more powerful.  Once you select a process, you get a parameter window opening.  SoundShaper Pro allows 16 different processes simultaneously; SoundShaper Lite can run 2 processes at a time.


This is the window for the Single-source Sample Sequencer.  There aren’t a lot of parameters to control here, but you can see at the right in the middle, a data window.  This is a text file in which you specify when, at what transpositions and at what loudness you pile up copies of a single sample.  There are also multi-sample versions of this and so on.  For other processes, there can be many parameters, each of which can be varied over time using either graphs or text files.  Here’s an example of a multi parameter interface, this one for the independent program GrainMill.


Notice the rows of parameters available, and in the far right column, a list of “Time Contours.”  In this illustration, I’m not using any of them, but each parameter – for both the upper range and lower range of a parameter, can have a separate time contour controlling it.  Needless to say, you can make VERY complex sounds with this method.

The SoundLoom interface works in a very similar way.  Here’s a shot of the basic SoundLoom interface.


Here you can see at the right, the contents of a source directory.  Files from this are placed on the Workspace in the middle.  Then files from here are placed in the Chosen Files list.  Files from here are then modified by clicking on the “Process” button at the upper left.


For this process, “Pitch:Speed tape transpose by time-ratio” there is only one parameter, so there’s only one control.  However, the “Range” button and the “Get File” “Make File” buttons allow you to apply a time-varying control signal to the transposition, so you can get changing transpositions on the sound.

Here are a couple of examples of how I used CDP in the past.  For “Samples IV,” a piece using orchestral samples, I was curious about how dense a texture I could make.  I took 12 orchestral samples, each of a different instrument and each on a different pitch.  Using the Sequencer Routines, I made a sequence of 1000 notes.  (I used John Dunn’s ArtWonk and a Spreadsheet Program to generate lists of 1000 pitches, 1000 timbres, 1000 durations, and 1000 loudnesses using various probability distributions.  These when combined, made the text-file for the Sequencer Routine.  I did this twelve times, getting twelve different sequences of 1000 notes each.  I then took the EXACT same text-file, and used it to pick and sequence the twelve different 1000 note sequences, making a texture with 1,000,000 notes in it.  I made a number of these sequences, and those were the main material of the piece.

Another example – on Labour Day, May 1st, I recorded an old favourite – a music box that played “The Internationale,” the international worker’s anthem.  I then used the “Pitch:Stack” routine to make 17 copies of the file, each 63 cents apart (that’s just under 2/3 of a semitone).  I used the routine in one pass to combine the 17 copies so that they would all begin together, and another version in which all the copies would end together.  I then spliced the two together so that the “all copies ending together” version came first, and the “all copies beginning together” version came second.  This gave me a texture that got thicker and faster until it came to a climax, which was immediately followed by a climax that gradually then got slower and thinner to the end.  I guess this was sort of a sonic version of revolution and counter-revolution, or maybe it was just a sound complex that got faster and thicker towards the middle.

As you can see, the emphasis of this program is not on making melodies or regular rhythms (although it’s certainly capable of that), but in exploring sound producing lots and lots of resources and sounds that you won’t get any other way.  For those interested in exploring sound, and finding new ways of modifying and combining sounds, the Composers’ Desktop Project is essential.  And what’s even better, it’s now free.

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