Dr.Godfried-Willem RAES

Kursus Experimentele Muziek: Boekdeel 5: Notatie

Hogeschool Gent : Departement Muziek & Drama

5600:

RAVEL

Ravel is een programmeeromgeving speciaal ontwikkeld voor algoritmische kompositie op de IBM-PC. Als taal heeft het heel wat gemeen met een versie van C waarin MIDI-operaties geimplementeerd werden.

Het RAVEL systeem bestaat uit drie hoofdprogrammablokken:

• MOS
• MC
• ML

MOS is een 'command-shell' en uitvoeringsmodule voor programmas.

MC is de Ravel compiler. (snel en via een enkele programmadoorgang).

Met deze beide blokken worden de cycli edit-compile-play bijzonder ingekort.

ML is de programmalinker voor Ravel. Gebruik makend van de Ravel import en export mechanismen kunnen modules of libraries opgebouwd worden die met deze linker gekoppeld kunnen worden en tot een finale EXE file gekombineerd.

ML en MC kunnen samen worden gebruikt om grotere toepassingen te ontwikkelen. MC op zichzelf volstaat voor kleinere programmas.

De belangrijkste eigenschappen van RAVEL zijn: (Overgenomen uit de programmadokumentatie):

1. Programming Language:

• . concurrency, parallel main threads (programs) that run against one event clock.
• . functions
• . include files
• . if-then-else; switch statement
• . for loop and break
• . note and time constants for music
• . almost all C expression operators supported
• . MIDI action statements, including note, rest, and tie operators plus ways to build chords.
• . predefined function library
• . one and two dimensional arrays. Integer and byte data types.
• . data may be put in global arrays and variables with C like initializers.
• . MIDI event aggregate data structure called a data action. This is a Ravel language subset that can be used for data import/export to sequencers.
• . data hiding/abstract data types with import/export mechanism.
• This is referred to as "encapsulation"; i.e., it is possible to build modules or packages with Ravel.

2. MIDI actions (events):

Most actions take expressions as operators; e.g.,

riff lousyMelody()

note C q forte

note 60 24 100

note mrandrange(C,HC) mchoose(q,e) mrandrange(100,120)

note ar[3] q*2 forte-x

tie w

rest w

end

would be note, tie, and rest statements in a riff or function. Each note action statement takes note, time, and velocity expressions.

• . notes include simple notes (event time = duration) and duration notes if elapsed time and note duration do not match. Complex chords can be built from duration notes.
• . simple chord statements
• . patch (program), pitch bend, continuous controller
• . dx7 param changes
• . metro - clock change
• . and others

MIDI actions may be declared as statements (code) or may be put in special arrays and treated as data. Actions as data represent a special action data type that is a union of action statement types.

3. Built-in predefined functions:

• . strong random number package including fractal generator and drunken walk routine
• . motif manipulation functions
• . console i/o
• . raw MIDI i/o
• . vector (scalar) array manipulation
• . MIDI oriented functions (linear scaled pitch bend)
• . action data executor
• . dynamic parallel mains (voicelist) may be spawned to run concurrently along with static voicelists.
• . built in window package for runtime manipulation and display of data.

4. Mos features:

• . Unix(tm)-like ls, cp, rm, mv.
• . can execute DOS programs (editors...).
• . can save current music setup in ASCII mos command file.
• . can execute commands from mos command file.
• . control tempo, set startoff patch, change per channel transpose or overall transpose.
• . can set simulation feature and save MIDI actions in per channel ASCII file. Subset of Ravel language.
• . timebase can be set from 24 beats per quarter to 240 beats per quarter in increments of 24.

5. New features:

Translation to and from CAKEWALK sequencer ASCII format. Ravel is now modular with a linker ml. The compiler mc has the ability to import/export global data and functions and build modula like libraries. There is a new beta-test utility mtor that translates MIDI File Format files into Ravel files.

Machines

1. IBM PC/ mpu-401 only.

Reviews

• 1. Music Technology. July 1988. p. 74.
• 2. Keyboard. Nov. 1988 p. 86.
• 3. Music Technology. July 1989. p. 57 (review of tape made using Ravel).

Cost

$30, $40 overseas. This price covers materials, mailing, etc. Ravel is now in the public domain. Feel free to give it to a friend. However, please try and provide that

friend with the manual. The manual may be copied. A loose leaf programming manual of about 300 pages + a 50 page appendix that describes new features and software on three disks are provided. Disk one contains executable programs. Disk two contains more executables and simple

Ravel music programs and example code. Disk three contains a jazz improvisation system built with Ravel and other more complex pieces.

Source

Source is available for the seriously inclined. I would estimate about 7 1.2 megabyte floppies are needed. That is the only media I will ship source on. I would be very interested if someone wanted to port it to the Mac or a Cray.

As of August 1990, Ravel is in the public domain. Software and manuals can be given away. No restrictions exist on use other than it should not be sold for profit. No warranty of any kind is provided. Use as is, at your own risk. Software and Xerox manual of original laser printed version is available from:

• Humworks - Jim Binkley
• 5814 SW Taylor
• Portland, Oregon 97221

There are a few copies of the original ATARI version available. It matches up with the original manual fairly well. Pricing info in the original manual should be ignored. Ravel is "for free". I can be contacted on USENET at jrb@jove.cs.pdx.edu . Portland State University.

Filedate: 900928