Musical Audio Research Station

The Musical Audio Research Station is a specialized digital machine for real-time audio applications, developed by IRIS (Istituto di Ricerca per l'Industria dello Spettacolo), the research institute owned by the Italian Bontempi-Farfisa group.

MARS was conceived as an interactive and integrated environment for audio research, musical production and computer music pedagogy. It is dedicated to people who have hit the limits of the digital musical instruments currently available on the market and would like a programmable and a flexible sound machine with real time performances.

SOFTWARE

A proprietary development system, the EDIT20 software package, is a set of specialized graphical editors featuring a graphic user-friendly interface that allows musicians to program the DSPs and to perform. They allow the development of algorithms, timbres, waveforms, orchestras and their MIDI performance environments - all sound objects which lead to musical (and scientific) applications.

One may connect, and immediately get audio feedback from, objects coming from an expandable library, so as to build any kind of patch and DSP algorithm for musical/signal processing such as sampling, analysis and synthesis, filters and sound effects.

The patch editor offers a set of more than 100 computing blocks in "iconic" MUSICn style representation. These blocks cover low and high level needs for DSP applications:

- - arithmetic and logical operators; - - many types of oscillators and complex generators such as FM, AM or NLD; - - time, spectrum, pitch and amplitude transformers such as delay, reverberation, filter, harmonizer, mixer and other effects; - - mechanical parameters for realistic simulation of physical models.

EDIT20 makes algorithm testing easy because it provides a set of debugging tools such as real time data displays, a four track oscilloscope, and audio probes which can be used at any connection point among the blocks.

EDIT20 can duplicate algorithms to create more voices and manage different types of algorithms simultaneously, allowing multi-algorithm sound processing.

HARDWARE

The MARS hardware is a standard 2U rack module which contains the SM1000 sound generation board and one DAC/ADC board which provides 4 analog inputs and 8 analog outputs.

The SM1000 board is based on two specialized DSP chips (X20) developed by IRIS, and one standard microcontroller (MC68302 Motorola) that supports the RT20M embedded real time operating system, managing MIDI messages and other system events.

The X20 is an ASIC (250,000 transistors complexity) digital audio signal processor, which is fully programmable. Its internal pipeline structure and direct connections among the operators create a computing power equivalent to 50 MIPS. See below for examples of the available computing power.

Each X20 has its own memory bord, holding sample memory for a total of 40 Mbytes, that is, about 9 minutes of sound memory or delay lines.

The SM1000 board needs to be configured before being used. This is done through a host computer which can be linked to the board via serial (MIDI) or parallel (VME bus) lines.

MUSICAL APPLICATIONS

EDIT20 can be used to build tones and orchestras because it allows musicians to adjust all the algorithms' parameters, to set envelopes and to edit samples.

The algorithm parameters may be associated with gestural MIDI controllers to allow dynamic updating by means of arbitrary conversion rules. Rules and data values can be defined interactively and graphically by using universal symbolic representations (physical or musical measure units such as Hz, dB, milliseconds, or musical notes).

MARS does not provide any compositional environment, but its compatibility with the MIDI world allows users to employ standard sequencers, MIDI devices and programming environment such as MAX (*).

The MARS MIDI implementation covers most of the standard MIDI messages and offers a set of system exclusive MIDI messages covering all system configuration operations.

Several complete applications are already included: LPC analysis and synthesis, vocoder, physical modeling, graphic FFT, etc., and many others can be developed by C programmers using the APPLI20 toolkit. A number of works of Computer Music have been produced (S. Sciarrino, L. Berio, W. Prati).

MARS is currently interfaced with Atari ST and TT computers via the VME bus, and porting to Macintosh and PC-Windows is in progress.

It is available directly from the manufacturer, in a limited series, with a price in the range of 10,000 US dollars, depending on memory configuration.

CURRENT MARS USERS

CSC - University of Padua DIST - Unversity of Genova CNUCE - National Research Center of Pisa Tempo Reale - Center for musical research production and pedagogy of Florence MM&T - Musical studio of Milano Spazio Musica Ricerca - Musical research center of Cagliari COMUS, FARFISA - of BONTEMPI group Physical Sciences Department - University of Naples Physical Sciences Department - University of Ferrara EDI-PAN - Centro di produzione musica informatica Heinrich-Strobel-Stiftung des Sudwestfunks E.V. - Musical studio of Freiburg Musik Akademie der Stadt Basel - Musical conservatory of Basel

CENTERS WHICH REQUESTED MARS

CCRMA - University of Stanford CNMAT - University of Berkeley IRCAM - Georges-Pompidou center of Paris CIRM - Musical center of Nice ACROE - Musical association of Grenoble LIM - University of Milan AGON - Musical studio of Milan Ensemble Edgard Varese - Musical studio of Parma

DSP FEATURES

Pipelined architecture, fully programmable. 2's complement fixed point arithmetic on 24 bits. 16x16 bit multiplyer, 24x24 bit arithmetic and logic unit. 768x24 bit words of internal data memory. 512x64 bits word of external program memory. 40 MHz system clock, 39.0625 KHz up to 1 MHz sampling rate.

EXAMPLES OF DSP PERFORMANCE

(using optimized assembly algorithms, one at a time)

128 second order filters. 256 fully controllable simple table-lookup oscillators. 128 fully controllable interpolated oscillators. 128 delay lines with maximum total delay time of 7 minutes. 32 independent harmonizers. 2 independent 2048 point FFTs. 32 voices of Karplus-Strong string algorithm. 32 voices of 4 operators FM algorithm. 2 voices of 25 cells LPC algorithm. In addition, 128 multi-segment envelope generators are always available.

AUDIO INTERFACING

4 balanced analog input lines, 1/4" TRS jack: CRYSTAL Delta-Sigma A/D converters. Signal/(Noise and Distortion) ratio > 90 dB S/(N+D) Internal 64x oversampling. Linear phase digital anti-alias filtering. 39.0625 KHz as standard sampling rate. 8 balanced output lines, 1/4" TRS jack CRYSTAL 64x Delta-Sigma D/A converters. 97 dB dynamic range over the audio band, A-weighted. Internal 8x oversampling. Linear phase filter. 39.0625 KHz as standard sampling rate. 2 stereo headphone outputs, capable of driving high impedance models (600 Ohm).

STANDARD CONFIGURATION OF THE TWO MEMORY CARDS (16 bit word)

2x1 up to 2x8 MWords of DRAM (32 Mbytes, 7 minutes of sound or delay lines). Standard SIMM modules, 80 ns (i.e. MC-421000A8, MC-424100A8). 2x256 KWords up to 2x2 MWords of EPROM, 120ns (i. e. 27C010/20/40/80). 1.75 minutes of preset samples.

SM1000 AND HOST COMMUNICATION

MIDI interface (IN, OUT, THRU). RS232 interface (19200 Baud). VME interface (500 KByte/sec maximum transfer rate).

OTHER SPECIFICATIONS

Power requirements: 100-240 v AC, 50-60 Hz. Dimensions: 2U standard rack module.

SOFTWARE PACKAGE

RT20M: Embedded Real Time Operating System. EDIT20: Interactive Graphical Development Environment. APPLI20: Application toolkit.

MARS PORT-FOLIO

CONFERENCES AND WORKSHOPS

X CIM (Colloquio di Informatica Musicale), Genova 1991 - IRIS Report Studio International Workshop, Capri 1992 - IRIS and CSC paper ICMC (International Computer Music Conference, S. Jose 1992) - Special session on MARS (5 papers) Sonic Representation and Transform, Trieste 1992 - MARS presentation and workshop Milano Musica, Teatro Studio, Milano 1992 - MARS presentation Virtuosismi virtuali, Palazzina Liberty, Milano 1992 - I nuovi strumenti e la prassi esecutiva Festival Spazio Musica, Cagliari 1992) - MARS presentation IRIS, Paliano 1992 - 3 days workshop on MARS Scuola Civica, Milano 1992 - 2 days workshop on MARS Live electronics in the works of L. Nono, Vicenza 1993 - 3 days workshop on MARS Experimentalstudio der Heinrich Strobel, Freiburg 1993 - Seminar on MARS Accademia Chigiana, Siena 1993 - Workshop on MARS Frankfurt Musik Messe, Frankfurt 1993 - MARS presentation

CONCERTS AND MUSICAL EVENTS

S. Sciarrino, Perseo e Andromeda, Festival delle Orestiadi, Gibellina 1991, Scala production, Teatro Lirico, Milano 1992 L. Berio, Ofanim, Festival d'Automne, Opera de la Bastille, Paris 1992, Jerusalem 1992, Berlin 1992 L. Nono, Post-prae ludium per Donau, Workshop on "Sonic Representation and Transform", Trieste 1992 - - A Pierre dell'azzurro silenzio inquietum, Terni, Perugia 1992 - - Das atmende klarsein, Vicenza 1993 W. Prati, L'isola nell'oasi, Scala production, Teatro Studio, Milano 1992 - - Puzzle, Nuove forme sonore, Teatro Politecnico, Roma 1992 - - Improvvisazione con E. Parker, Total Music Meeting, Berlin 1992 G. Palmieri, Unknown title, Teatro Verdi, Genova 1993 - - Frankenstein e Pinocchio, Colombiadi Production, Teatro Altrove, Genova 1993 - - Unknown title, Palazzo Ducale, Genova - 1993 S. Gorli, Unknown title, Scala Production, Teatro Lirico, Milano 1993

ALGORITHMS AND RESEARCH

Synthesis: Additive Subtractive PCM based Linear Arithmetic Frequency modulation Phase modulation Wave shaping Phase distorsion Physical models (strings, winds, singing voice) LPC (Speech) Analysis: FFT Vocoder FIR and other filtering Envelope following Pitch following Effects: Pitch shifting Reverberation Chorus Leslie Delays Doppler effect Panning and mixing Research: Perception paradoxes and psychoacoustics Industrial noises simulation Sampling interpolation and data compression Rhythmical accompaniment Timbre interpolation Analog synthesizer simulation Simulation aid design for DSP hardware

MUSICAL DEMOS

Dr. Livingtones I presume - PCM + FM + additive synthesis Ostinato - Karplus-Strong + PCM synthesis Il Re (The King) - Karplus-Strong + LPC + physical models of clarinet and singing voice Kaos - Composition environment based on chaotic parameter maps Automath - Stochastic composition environment Vocoder - 12 channels real time analysis and synthesis Delay - 64 parallel delay lines for live performance

SCIENTIFIC DEMOS

FFT - 2048 points real time 3D FFT Image - Filtering of 2D grey pictures Space - Simulation of a moving sound source by means of Doppler effect Avion - Simulation of airplane noises

PEDAGOGICAL DEMOS

AS - Environment for additive synthesis with 100 components Corda - Environment for string modelling by means of springs and masses

BIBLIOGRAPHY

S. Cavaliere, G. Di Giugno, E. Guarino, "MARS: The X20 device and SM1000", Proceedings of the ICMC, pp. 348-351, S. Jose, 1992. P. Andrenacci, E. Favreau, N. Larosa, A. Prestigiacomo, S. Sapir, "MARS: RT20M/EDIT20 - Development tools and graphical user interface for sound generation board", Proceedings of the ICMC, pp. 340-343, S. Jose, 1992. F. Armani, L. Bizzarri, E. Favreau, A. Paladin, "MARS: DSP environment and applications", Proceedings of the ICMC, pp. 344-347, S. Jose, 1992. G. Palmieri, S. Sapir, "MARS: Musical applications", Proceedings of the ICMC, pp. 352-353, S. Jose, 1992. A. Paladin, D. Rocchesso, "A Dispersive resonator in real time in MARS workstation", Proceedings of the ICMC, pp. 146-149, S. Jose, 1992. A. Paladin, D. Rocchesso, "Toward a generalized one-dimensional musical instrument", Proceedings of the International Workshop on Models and Representations of Musical Signals, Capri, 1992. D. Rocchesso, "Realizzazione di risuonatori dispersivi in tempo reale", degree thesis in Electronic Engineering , University of Padua, 1992. E. Favreau, A. Prestigiacomo, "ASM20 User's Guide", IRIS internal paper, 1990. ITIS, "SM1000, DREP and ADDA technical description", IRIS internal paper, 1991. IRIS, "Musical Audio Research Station - User Guide", IRIS internal paper, 1992. (*) MAX is an Interactive Graphic Programming Environment developed at IRCAM and distributed by OPCODE SYSTEMS. IRIS srl - Parco La Selva, 151 - 03018 Paliano (FR) Italy Tel.: +39-775-533441 - Fax: +39-775-533343 - email: mc2842@mclink.it

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