Page  78 ï~~Studio Report Computer Music Department of CNUCE/CNR, Pisa - Italy via S.Maria 36 - 56126 Pisa Tel. 050/593276 - Fax 050/576751 E.mail: Music5 @ ICNUCEVM.CNUCE.CNR.IT Leonello Tarabella Graziano Bertini Abstract: Traditionally Computer Music has been present and active in Pisa for several years. Activities at the Computer Music Department of CNUCE/CNR are now carried on by Leonello Tarabella (Coordinator), Graziano Bertini, Paolo Carosi and Alfonso Belfiore. The group mainly deals with the following topics: Personal Computer based Music Workstation design and prototyping, Development of Software for composition and interaction, Education and Organization of concerts and special events. Keywords: Music Workstation, Digital Signal Processing, Algorithmic composition, Interaction Introduction The CNUCE Istitute belongs to the Italian National Research Council (CNR). Nowadays at CNUCE/CNR in Pisa, more than 120 employees work (over 50 as researchers) in various fields of Computer Science: Logic programming, Networking, Satellite flight control, Data Bases and VLDB, Parallel processing, Image processing, Remote sensing, Computer Music. Research in the field of Computer Music began at CNUCE in the early 70s, and are now carried on by Leonello Tarabella (Coordinator), Graziano Bertini, Paolo Carosi and Alfonso Belfiore. Furthermore there exists a privileged link with the Conservatory of Music in Florence where a group of researchers led by Lelio Camilleri mainly deals with problems on musicology. [see ARRAY vol.11 n.l, pagg 3-6]. The activities at the Computer Music Department of CNUCE/CNR in Pisa mainly consist of Applied Research, Education, Music production and Organization of concerts and special events. As regards the Applied Research, different kinds of hardware and software tools are implemented to be used for setting up music workstations. Commercial machines such as Synthesizers, Samplers and Sound Processors, do not completely satisfy the typical requests coming from researchers in acoustics and, more important, from composers. Still today these requests can only be satisfied in very few centers in the world; so, the need of flexible and actually programmable machines which may be available at personal level, is more and more felt. Music workstation Nowadays the Market provides personal computers and electronic devices with ever-improving performance capabilities at increasingly lower costs. All that allows the design of systems which are able to exploit various and complex functions and can be used for assemblying music workstations easily re-configurable for different kinds of ICMC 78

Page  79 ï~~situations. At the Computer Music Dept. of CNUCE the following topics are dealt with: - design of digital systems for audio signal processing; - design and carrying out of software tools for the definition of synthesis algorithms and audio signals processing; - formalization and developing of environments based on programming languages for composition and interaction; - design and carrying out of special sensing device to be used during the live-performance. The following figure represents the building blocks of a generic workstation for music and acoustic signal processing; it is possible to identfy at least three different levels: the hardware level, the system software level and the level for composition and performance. Input devices Software for level 3 for interaction Composition Personal Graphic level 2 Syesoft r,Editor/Compiler COmputer for synthesis algs level 1 Programmable I devis DSP devices Level 1: hardware As concerns the first level, our work mainly consists of designing and carrying out special hardware devices based on VLSI electronics such as Digital Signal Processors, Programmable Logic Array and Dual port RAM chips. Regarding Midi standard machines, our work consists of designing and carrying out the proper hardware and software interfaces, when and where necessary. After a period during which we carried out some prototypes of cards using DSP microprocessors belonging to the Texas Instruments TMS320 family [1,2], recently we developed some cards PC-IBM bus-compatible designed around the TMS320C25 microprocessor. This project was possible after a collaboration with the CAD and Electronic Assembly Labs of the Istituto di Elaborazione dell'Informazione (L.E.I./CNR) Pisa, and the Centro Tecnologico Culturale "Leonardo", Massa. The Centro Leonardo also put on the market a version of the card labeled as Leonard'C-25 [3]. The main characteristics of this card, besides the computing capabilities of the TMS320C25, are the presence on board of a large amount of zero wait-states memory (128K-words DataRAM, 64K-words ProgramRAM, 4K-words Eprom), and serial and parallel ports for controlling D-to-A and A-to-D converters. ICMC 79

Page  80 ï~~Since generally speaking a single board is not enough to solve problems concerning complex musical situations, a multi-processor architecture device is under development [4]. The goal of this project is to get a flexible and expandable system that will provide computing capabilities of 100 MIPS and over. At the moment we are carrying out a prototype of this device by using a number of Leonard'C-25 cards plugged in the bus of a PC-IBM computer. This arrangement also allows to develop and test the proper system software. Level 2: System software A special program for managing the multi-processor system capabilities, has been developed. Due to its functions, this program can be truly considered as an operating system; in fact it performs the following tasks: - system initialization, consisting in the allocation of synthesis and processing algorithms on the variuos processors [5]; - runtime control of acoustic parameters during the execution of music. It is worthwhile to highlight that with processing algorithms we mean both the classic sound processing features (echo, delay, flanging...) and original real-time procedures such as, for example, pitch and mean-volume detection. In order to facilitate the definition of synthesis and sound processing algorithms, a Graphic Editor/Compiler running on Macintosh machines has been developed: using the mouse, it is possible to place on the graphic window symbols such as generators, envelope shapers, delays, adders... taken from a palette, and to link (and unlink) them with tools like pencil, eraser... The Editor/Compiler includes an online syntactic analyser that guarantees the correctness and the consistency of the drawn algorithms. The drawing is then translated into a DSP machine code. [4] Level 3: Software for composition and Interaction Following the tradition of using programming languages to compose, a special environment, called PascalMusic [6], has been developed. PascalMusic consists of the standard Pascal language enriched with a set of primitives that control music and acoustic parameters. A peculiarity of PascalMusic is the possibility of interacting with the program/composition during the execution: a special primitive (Filter) allows to sense selectively actions performed on external devices (keyboards, drum pads, pitchto-midi converters,etc..) and to make decisions on the basis of gestures of human performers. PascalMusic has been developed has a guest of THINK PascalTM (Symantec) and Turbo PascalTM (Borland), and can be used for controlling (and to be controlled by) Midi-standard devices as well as special DSP devices. At the moment work is being carried out in order to supply PascalMusic with the features of parallel programming: in this way PascalMusic will be more elegant and powerful, and interaction will happen simply by affecting variables values from the outside world. Where interaction is meant to be part of the composition, standard Midi-IN devices (keyboards, drum pads, pitch-to-midi converters,..) are usually used. Further, sensors typically used in robotics, are taken into consideration in order to carry out special devices: in collaboration with the Advanced Robotics Technology and System Lab (Scuola di Studi Superiori Universitari e di Perfezionamento S.Anna, Pisa) two ICMC 80

Page  81 ï~~such devices, the Pyramid Infrared Midi Event Generator that detects the movements of a hand palm, and the Light Baton, that detects the movement of an orchestra director, have been developed [7,8]. Education and Diffusion A course on Computer Music is yearly teached by L.Tarabella at the Computer Science Department, University of Pisa. As a consequence, many students graduate developing their thesis on Computer Music topics. The Computer Music Department of CNUCE also organizes concerts of computer music and special meetings like the recent International Workshop on Man-Machine Interaction in Live Performance which took place at the Scuola S.Anna, Pisa, and special meetings such as the "Seminar/Concert" at the Accademia Chigiana, Siena. Biographies Leonello Tarabella began his musical training as alto-sax player. He received his Ph.D. in Computer Science from the University of Pisa and since 1977 he has been working as a researcher at the Computer Music Department of CNUCE/CNR, Pisa. He yearly teaches the Computer Music course at the Department of Computer Science of Pisa University. His research the development of environment for composition and strategies for man-machine interaction; also, he composes and performs his own music. Graziano Bertini received his Ph.D. in Computer Science from the University of Pisa, Italy, and since 1975 he has been working as a researcher at the Image and Signal Processing department of IEI/CNR, Pisa. As a member of the Computer Music Dept. of CNUCE/CNR, his research mainly deals with the design and prototyping of microprocessor based systems for real-time sound processing. Paolo Carosi received his Diploma in Flute and Compositon from the L.Boccherini School of Music, Lucca. He studied with MÂ~Severino Gazzelloni at Accademia Chigiana, Siena. As a member of the Computer Music Dept. of CNUCE/CNR and an expert in computer science, he develops his own hardware and software. He composes and performs his own computer music. Alfonso Belfiore received his Diploma in Piano and Composition from the G.Verdi Conservatory of Music, Milan. Since 1980 he has been yearly teaching the Electronic Music Course at the C.Pollini Conservatory of Music, Padua. He is also member of the Computer Music Dept. of CNUCE/CNR. He is the author of electronic and computer music, and multimedial operas. References [1] Tarabella L., 1987. The Primula Machine - Computer Music Journal (MIT Press) - 11(2) [2] Tarabella L., Bertini G., 1987. Un sistema di sintesi ad elevate prestazioni controllato da personal computer - Quademi di Musica/Realtk n. 14: Atti VI CIM - Unicopli, Milano [3] Bertini G, DelDuca L., Marani M., 1991. The Leanard 'C25 system for real-time digital signal processing (abstract) - International Workshop on Man-Machine in Live-Performance - Pisa [4] Bertini G.,Tarabella L., 1989. A digital signal processing system and a graphic editor for synthesis algorithms, Proceedings of the ICMC89 - CMA, POBox 1634, S.Francisco, Ca. [5] Jaffe D., 1990. Efficient Dynamic Resource Menagement on Multiple DSPs, as Implemented in the NeXT Music Kit - Proceedings of the ICMC9O-CMA, Glasgow. [6] Tarabella L., 1990. Algorithmic composition and interaction, Array CMA Newsletters, 10(4) [7] Buttazzo G. et alii, 1991 - Infrared-Based MID! event generator (abstract) - International Workshop on Man-Machine in Live-Performance - Pisa [8] Carosi P.,Bertini G., 1991 - Light Baton: a system for conducting computer music (abstract) - International Workshop on Man-Machine in Live-Performance - Pisa ICMC 81