AMADEUS - Computer Assisted Music Perforating
By Robert Hopp
Niederviehbach, 7. October 1996
AMADEUS
Computer Assisted Music Perforating Machine
Part 1 : Mechanical Function and History
This AMADEUS was born in summer 1992 after 6 long years of searching and building. Between the idea and the certitude "that it is possible" and the first music without distortions or "computer-sound" was a long way of hunting little devils of details. I also needed to meet the right person: Doctor Patrick Sanchez, of the CNRS (Centre National de Recherches Scientifiques) of Marseille in the south of France. This genius man was the first one to understand my dream of making perforated music without suffering (and who had the scientific package to help me in this adventure) !
So we seat down on a table, looking on the Mediterranean Sea under the wonderful light of the French "Provence" and put together out ideas in front of a glass of "rose".
In the beginning I thought I knew what I wanted but in getting further on with working on the system I had to understand that the problem was much more complicated than I thought ! "Easy" things now seemed difficult and difficult things did not take time at all. But between me and Patrick was (and is) respect and comprehension of a beginning friendship and so we went on efficiently.
After our first session I could start building all the mechanic parts of the machine.
I choose a wooden structure because it was easy for me in my organbuilder-workshop to make one, and, as my father was constructor of robots and wooden aircrafts, I had good knowledge between my childhood in building light and easy complicated things. Another reason was, that I wanted Amadeus to be able to travel easily in my van to be able to make demonstrations outside.
The punching-tool itself is traveling in the y-axis on a carriage with longitudinal ball-bearings. The paper or book is driven in x-axis by rubber-rolls, both axis are powered by step-motors with 2/100 mm steps. That is the best resolution, it makes no difference if you make it higher, the paper would not "feel" it. In "human" punching-systems I observed best results (in the morning, no head-ache, no lover's grief) of 0.5 mm, normally 1 mm. That makes 1/60 of a second calculated with normal speed ! I researched tolerance-limits of "normal" people in making tests with music and found out that 2/100 of a second are perceived. Trained musicians or instrument-builders can hear better than 5/1000 sec. That is about 0.3 or 0.2 mm on a roll or book !
We have here the difference between "music" and "mechanical" music. And we find here the reason why one can make very nice music with a MIDI system : it punches exactly what you can hear before and even the copy number 37 is as good as the first ! The quality of interpretation is more important than understanding how it goes, that means that musicians having no idea how to sharpen a punching-tool or folding cardboard-books or adjust a complicated machinery can concentrate on their real work: making music. This opens a lot of possibilities for many people. One of the reasons that made me choose a MIDI compatible system and not one more "internal standard", was the opening on the world of thousands of musicians in the whole world able to write or even "record" music for mechanical instruments as long as they have a computer and know how to generate a MIDIfile after reading a precise scale. It is one more time possible to make records of famous musicians as in the beginning of the century with reproducing pianos.
But I come back to the mechanical parts of Amadeus: the punching-tool is changeable in a few seconds, with one screw, so it is possible to make holes of any size or form: round or square. The matrix is interchangeable too. So I have sets of tools in any shapes and sizes. It is possible to make sets for metal music-box disks and to copy or create any shape of pins in the matrix, but I never did it. It is also possible to punch disks of metal sheet or cardboard. My request was to make a universal system with Amadeus.
The paper (or cardboard) comes between adjustable guides with a maximum width of 500 mm. It is possible to punch up to 20 paper-rolls at once or 2 thick cardboard books for fairground-organs. There is a system to deliver correctly the papers with individual brakes on each roll. On the reception side are universal rolls to wind up ready punched paper stripes. The folded books fall in boxes.
According to the side where the guide-side is, left or right (or up or down) I punch from the upside or turn it around. So I am sure that the paper or books are always adjusted on the trackerbar. It takes about 2 hours to finish a "normal" music, but the machine works without any human control, day and night, so it is possible in theory to make 240 rolls a day or 24 music-books. I made a control system that detects lack of paper or any other problem, it stops the system and calls me, even in my bedroom. Fortunately this is rare. But as I make music for theater, television, video clips and other productions, it is sometimes necessary to make and deliver music very quickly and it is not possible to waste a night.
There was a choice in the beginning: to make a rather slow machine with a single tool or a much faster and easier system with a whole rank of tools in the right division. But it was clear for me, that a universal system could have only one punching-tool moving in x-y coordinates. It is also a question of hardware how fast it can be. A simple paper roll machine could be faster because the tool is much lighter, but it takes about 500 N/m to perforate a thick cardboard instead of 100 of 200 N/m even with many layers of paper. So the weight my moving part is about 20 kg. The other reason of this weight is the width of almost 450 mm. But many big organs, orchestrions and pianos have this size. The PC is connected with serial bus (as a mouse) to an interface were the TTL signals are interpreted in powerful commands for the motors. The step-motors have to be strong and the interface must supply many amperes. All that needs cooling in the summer, but small integrated ventilators do the job.
The U formed part where the punching tool and the matrix are fixed, is driven by a screw and a nut with ball-bearings, no play and easy to turn. It is out of special hard steel, I had to make 2 other of them from ordinary construction-iron before I understood that any elasticity in that part was really a problem. It had to be very stiff and in the same time as light as possible. In the meantime I made 2 other machines and the problem is resolved to my full satisfaction.
The punching-tool is gliding on adjustable longitudinal ball-bearings too and has no play. That is very important because it is impossible to cut thin paper properly without a absolutely precise tool. It is driven by a eccentric and an electrical clutch that makes only one turn at a signal. I tried out magnets, pneumatic and hydraulic devices, but only the eccentric is fast enough and one can be sure that it went through even at the end of the week, when the tools needs sharpening...
In a few days I will talk about software and MIDI problems.
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| Quercus Edition - Robert Hopp ---------- -------
| Erlenweg 16 --- ---
| D-84183 Niederviehbach --- ---
| Germany ----------- -- --- ------- ----
| Tel : +49 (0) 8702 91183 -- ---
| Fax : +49 (0) 8702 91184 -- --- --
| e-mail : Robert.Hopp@landshut.netsurf.de --- --
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(Message sent Tue 8 Oct 1996, 17:42:54 GMT, from time zone GMT-0700.) |
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