Special Features of CDP
Sound Transformation Tools

Off-line processing

• CDP software places the emphasis on off-line processing, while beginning to create real-time plugins where appropriate (hear the result as you alter the parameter values).



• Many advanced processes are inherently non-real-time, and software which does not allow for or has minimal facilities for off-line processing is seriously limited in scope. Non-real-time processes include those which involve reading ahead in the input file, such as time-stretching, segment overlap looping, and re-arranging the order of segments or analysis windows drawn from the infile. The majority of CDP's facilities are in this 'off-line' category.



• How many parameter values can you adjust in real-time – 2? 3? With off-line processing, you can set up 5, 10, 20+ parameters to interact so as to create enormously complex results. The CDP Texture Set is a prime example, and long textures of multiple sound events can be designed with great precision and complexity and then created in a single processing sweep. CDP software therefore favours thoughtful design skills.



• Also, crucially, time-varying parameters are available in the off-line scenario. They are composed via time + value 'breakpoint files' rather than determined interactively.



• The complete CDP System offers a wide range of powerful processing facilities that are either not available elsewhere or are part of considerably more expensive systems. Our policy is to maintain off-line facilities (even when duplicating them with real-time options) because we consider it important for composers to be able to work in this way.

Real-time processing

• The great advantage of real-time processing is that you can hear the results as the parameter value is altered. Thus the way the various parameter values affect the input sound can be explored very quickly.



• It can also be possible to record the time-varying alterations in parameter values, thus preserving an 'automation' file for future use. It is important that this file be able to edited by the composer so that there is control over the fine-tuning of the results.



• You can experience some CDP real-time facilities by downloading our free prototypes from Richard Dobson's Website.



• Our real-time work at this time is focused on the spectral domain and makes use of Richard's customised streaming phase vocoding. It also has a multi-process and multi-channel capability.

Editable automation

• One of the key features of the CDP System is the presence of time-varying control for almost all the parameters. In accord with CDP's approach to musical composition, this makes it possible to sculpt the sound in time with extreme flexibility and precision, and to create complex passages of music even with just one program.




• The purpose of automation facilities is to enable parameter-variation over time.



• Composers know that the ability to change various aspects of a sound over time is crucial to achieving truly 'musical' results.



• In some systems, automation means recording actions which alter parameters as they are changed in real-time.



• CDP's approach has focused on the creation of time value 'breakpoint' files in order to automate change-over-time. This is a generic approach required by its extensive range of non-real-time operations. These files can be created with a text editor, or with one of the three graphic breakpoint file editors available with CDP software: the Brkedit program which is both standalone and accessed from within GrainMill (granular sound modifier), and the editors built into the two graphic user interfaces, SoundShaper and Sound Loom.



• The fact that these breakpoint files can be edited with a text or graphic editor gives users complete control over the fine-tuning of their composition. It also makes it easy to adapt the same data shapes to a variety of different parameter types: cross-parameter design work, an important contributor to compositions which evolve organically.



• Automation in a wider sense is possible via the use of Presets in the SoundShaper GUI, Patches in the Sound Loom GUI, and Settings in GrainMill. These are all mechanisms by which you can SAVE and RELOAD parameter settings, either just to use them again another time, or to apply the same settings to different source sounds.



• Finally, Tabula Vigilans offers scripting facilities for generating algorithmic MIDI or Csound score files. Richard Orton has done this by designing a careful selection of low-level functions that form the building blocks for musical processes of every description. The Csound connection is important, because it makes it possible to apply the processing to audio files. In addition, Tabula Vigilans can operate as a real-time MIDI musical instrument, as it updates parameter values at machine speed. For those with programming experience, this can be a very powerful tool indeed.

Chaining sound transformation processes

It is important to realise that the best sonic sounds achievable with the CDP software are very often not done in a single pass. The software and its various working environments make it possible to access the many different processing functions individually. As the result of a given process is accepted and saved as a new soundfile, this soundfile then becomes the input to another process selection. Thus processes are chained and the sound-sculpting results cumulative.

This is one of the reasons why it is difficult to provide demonstration sound examples for the software: the really good sounds are frequently aways the result of a series of operations which are difficult to describe to a non-user without becoming too complicated and obscure. The Sound-Builder examples on the DemoDisk are an attempt to illustrate chained processing.

Such sequences of operations can be preserved as Instruments in the Sound Loom front end for the software, or as DOS batch files. The SoundShaper history function produces a text file which can be edited to create a batch file.

As time goes on, the experienced composer builds a library of his or her own specialist, personalised tools which can speed up the compositional process in accordance with his or her individual style.

Last updated: 3 April 2005