Marc Marc Sound Mover SM 132 The SM132 can move sounds over 32 loudspeakers. It is part of the Sound Moving Installation that as a whole is controlled by software. For each Sonic Art project I write new software, inspired by the location. The Sm132 Interface count 32 analog multipliers, digital to analog converters and a data interface to connect to a computer. Amsterdam, Rotterdam, IJmuiden, Holland, The Netherlands, Germany Berlin, Rimbaud, Art, Kunst Data and Diagrams Technical

test & modify setup

test & modify setup

Some ex pla nation Amsterdam, Rotterdam, IJmuiden, Holland, The Netherlands, Germany Berlin, Rimbaud, Art, Kunst Each Multiplier - a Voltage Controlled Amplifier (VCA) - acts like a volume controller for the sound source that is connected to it. The voltage to control the VCA usually provided by the digital to analog converters (each VCA has one). These converters receive their data either from the parallel interface that can be connected to any printer port of a computer or via a MIDI connection. Thus, the volume of each VCA can be controlled by software. The data to send for controlling any of 32 channels is simple: 240+ID, Channel, Volume. '240+ID' inits the start of the data string. 'channel' is the channel index number (0...31 for the SM132) and 'volume' is the volume value (0=off....239=max). Amsterdam, Rotterdam, IJmuiden, Holland, The Netherlands, Germany Berlin, Rimbaud, Art, Kunst Moving When you turn the balance pot of your amplifier up and down, the sound will move from one loudspeaker to the other. In that case there are only two loudspeakers involved but it also can be done with more than two. The computer then suits very well for this job. To have a sound moved over a group of loudspeakers one needs to make a software algorithm that calculates the correct values for each channel to manipulate the volumes for each channel in such a way that the sound is moved following a certain choreography. When hardware like the SM132, the required amplifiers and loudspeakers are available, the moving of the sound(s), no matter how complicated, only is a matter of software algorithm. For the SM132 I wrote a various range of software tools on the Atari ST. From simple algorithms to only sweep several sounds with a fixed choreography up to complete menu controlled applications that able to edit and record the choreography for each sound channel to be moved.

Flexibility When a sound needs to be moved over a set of 32 loudspeakers, this requires also 32 power amplifiers (or 16 stereo ones). When, in 1988, the Sonore Theatrum project was launched in Amsterdam - The Milkyway (by Willem de Ridder & Radio Rabotnik TV) we had 32 stereo amplifiers and 64 loudspeakers. But, a set like this is an enormous ballast in both size and weight. For most projects a set of 16 loudspeakers is enough. In combination with the SM132 this 'minimized' setup becomes very flexible. It is possible to let two sound sources move over the 16 loudspeakers (2x16=32) or to let 4 sound sources move over 2x8 channels (4x8=32) or to let 8 sound source move over 4x4 channels (8x4=32). because all VCA's are individual to patch it is also possible to use them for the master volume of each sound before it is balanced over the multi channel setup with the others. Each VCA that will be used for another purpose can not be used anymore for the moving (make sense). But, in many situations there is no need to use the full capacity of 32 channels and thus the 'unused' VCA's can be used for mastering. This give the advantage that the computer can keep sending the full dynamic range of the volume data while the mastering takes care about the actual volume of the sound sources. it all becomes a matter of making the right patch on the SM132 panel and adapting this information into the software. Analog vs Digital The reason that the mutipliers are analog and not digital lays in the fact that with digital multipliers chips it is (at the time) very hard to make a silent system. With the commercial digital multipliers it even is impossible to prevent that the controlling data (2000 bytes per seconds) does not feed through into the audio signal. By using the 'old' analog principles it is possible to make a silent system with very good specifications. With the analog technique other problems occur but they can be solved by having the knowledge about this technique in contrast to the digital technique where the money becomes a significant factor). Horse The SM132 served me through the years very well with my sonic projects. It never fails, is insensitive to garbage on the outlet lines, does not heat up and can work 24 hours a day. Its a good horse. Goody old Atari ST The computer that I use to control the moving sound system is, still after all these years, the Atari ST. In contrast to the IBM compatibles running under Windows or Dos, the Atari does not crash at the wrong moment. Its system is relatively simple and more integer. The 8 Mega Hertz clock is due to the 68000 architecture of the ST fast enough (you would be surprised). The reason that I'm telling this is because of the fact that in my projects it is very important that the whole setup is extremely stable. The installation and all the sound devices, must be switched on with a single power switch and then start up automatically and do the job for many hours a day for many weeks without any experts being around. This excludes any commercial IBM machine and definitely the up to date machines that are running too much on high heels with the hardware. Secondly, the todays operating systems are too complex (and the writers of them are suffering on the disease of Alzenheimer) to guarantee a full proof operation over the required period. My goody old Atari ST beats them all when it comes to safety.

Back to Sonic Arts index . . . Back to main Index Also view the GEAR catalog which contains many informative chapters on analog musical devices and fundamental issues on electronic music. For response see Marc Marc contact file or email to marcmarc@xs4all.nl This page and all contents: (C)1996 by Marc Marc Amsterdam All technical pages are using a STYLE SHEET to set the font style. Please make sure that you have the option Style Sheet and Java Script are set enable.