Page  576 ï~~MIDI generation of sound morphologies Serge de Laubier, Daniel Teruggi INA-GRM 116, av du President Kennedy 75786 PARIS cedex 16 FRANCE Tel:,(33-1) 42 3021 82 Fax: (33-1) 42 30 49 88 Abstract:This demontration introduces the "MacSoutiLs" of the GRM, a set of MAX patches for the generation of sound morphologies with usual' synthetisers and samplers. The design of the algorithms uses models of dynamic mechanical systems and stochastic phenomena, such as bounce, spinning of objects, friction on a granular surface. The physical devices used for the control of the MIDI streams are a standard MIDI keyboard and a box of 8 linear faders. Introduction The "MacSoutiLs" are a set of patches working with the Opcode commercial version of the Max software, on the Macintosh. They have been designed for real-time processing of MIDI data coming from a MIDI keyboard and a box of 8 MIDI faders. Destinated to composers, they offer a convivality and share a common set of utilities like: saving of parameter values and sequences, display of the various parameters, matrices for the assignment of the faders and of the MIDI channels, etc... Five different softwares have been designed up to now: Rebond (bounce), Hasard (random), Lanceur ( thrower ), Grain-Glisse ( grain-slide ), Metro (-nome). ICMC 576

Page  577 ï~~Rebond (bounce) transforms in real-time the MIDI data coming from the keyboard for the simulation of bounces of objects. The likeness to the reality can be modified by several parameters (positive or negative gravitation, sensitivity, pitch diversion, etc...) that can be modified with the mouse or with the faders. The pitch of each note played on the keyboard defines the pitch of the first bounce; its velocity defines the initial amplitude and time interval between to successive notes. Hasard (random) generates random streams of MIDI notes. The pitch, velocity and flow values can be controlled in real-time. The pitch and velocity of the input notes define the mean values of the parameters of the output stream. Lanceur (thrower) is a software that simulates the "wheel of the fortune". The sliding speed of the faders defines the swinging speed of the wheel. MIDI notes are generated in a slowing down process, depending on the duration of decline. The pitches are controlled by the keyboard in two different modes. It is also possible to "freeze" the movement, to introduce some random variation, etc... The total polyphony is of 4 simultaneous processes, each of it generating a large number of notes. Grain-Glisse (grain-slide) offers various controls on loops played on a multitimbral sampler. A polyphony of 8 simultaneous loops is available, by the use of 8 MIDI channels. The parameters of each loop can be modified in three modes Â~:"microtonality", "granulation", "sliding". These cumulative control processes are associated with different modes of generation of the pitch bender data. All the parameter variations can be controlled in real time with the mouse and the MIDI faders. Metro (metronome) is a software that simulates the echoes of a metronome beat. A great number of modifications of the initial model are available: inversion, random repetition, associated pitch diversion, etc... The notes played on the keyboard define the pitch and velocity of the note repeated in echo. ICMC 577