Introduction: The wooden leg walking by itself
Who doesn't know the student's dream of being visited by a muse planting every kind of knowledge in his brains? Who hasn't been wondering about the existence of a magical pill that makes him omniscient? These kinds of visions are also in the minds of many musicians: how would they love to possess a potion which gives them the instant possibility to interpret any given score, without any technical difficulty. Or, in the composer's case, what about a means to translate his/her musical concepts directly into a score, or even better: into the sonic level?
Sadly, reality is organised in a different way: years of study and practice are needed in order to achieve intellectual and technical control over anything. Next to this, any tool conceived by human imagination is seldom more than a prothesis, never able to become a true interface of his/her own body. The tool may even become a problematic affair in itself, asking for years to overcome the struggle between the needful brain and the annoying instrument.
Then the automaton is a prothesis which has freed itself from its carrier to live its own life: the wooden leg walking by itself. Human fascination for the automaton is as old as the technical possibilities of manhood itself, especially when the machine is able to fulfill tasks that lie within the 'intimate' area of human expression: let's think of the fairy tale of the emperor and his nightingale. Wouldn't we hope to put an end to our own deficiencies?
Also, a declaration of the overwhelming success of sound recording and its playback since the beginning of the 20th Century, may not be confined to the fear of silence and the discovery of our own existencial silence, as Adorno thought.
Curiously, a conservative nostalgia to a romanticised and often wrongly interpreted past tends to point to automatons in a negative way: we oftenly see them as threatening antagonists, as substitutes to that noble, unique and eternally superior man. Nevertheless, any rational explanation fails for such a point of view, or better: sentiment. What could be wrong with the human product par excellence, the result of his expressive willfulness, the fruit of his creativity?
In order to create a useful machine, one needs constructive ideas. Automatons ought to be adapted to achieve full control over it; we need to take the power over the machine by tailoring it to our own needs and those of the society. At this moment, the building and designing of automatons has made a development from craftmanship and manual workmanship to the cerebral workstation. Today's robots are constructed in a less specific way: software development has taken a much larger place in this open-end concept. The workshop's function is restricted as being the place where prototypes are developed.
A computer and a set of healthy, open-minded and logically thinking brains are enough to write software and to conceive an instrument, in this case: a means of total instructional control over the machine. Laziness may be an argument against this way of thinking, but if laziness is leading us to a bigger amount of energy reserved to the process of creativity, then we'd love to be lazy! Music could be played in a better, much more joyful way if the player is elevated above the technique!
Dr. Godfried-Willem Raes
(English adaptation by B. Forment)
Logos automatons: a selection
A computer controlled acoustic harmonium with touch control and individual registration. The starting point for this construction was an old Hamilton suction reed organ, of which we only kept the reeds and the key springs. A new electric compressor was added (a small Laukhuff Ventola, rated for 50mm H2O pressure and 1000l/m). Since this compressor was pretty noisy in operation we designed a special silencer around it.
To control the individual reeds we used Laukhuff pallet electromagnets. As usual in our instrument designs, we designed a welded frame for the entire magnet and electromechanics assembly. Since there is no keyboard we could lower the force required to push the pallets from the original value of 2.45 to 2.94 Newton to about 1.2 Newton. Since the magnets are wider then the distance between keys/pallets, we had to mount them on alternating rows. The types we used are 20mm wide. The two registers are are each divided in a bass and a discant unit. So we provided also controll for these 4 registers. This was implemented using solenoids with variable voltage, such that gradual changes ('expression') become very well possible.
As a little extra we added a real cast bronze bell as well as a few lights to the mechanism
The note range of the instrument is 29 to 89 expressed in MIDI notes. The finished instrument has the following dimensions: depth 320mm, width 920mm, heigth 1000mm. The weight is ca. 50kg.
For the electronic control of our instruments we used our own <GMT> software in combination with the hardware we designed for player pianos. Thus the instrument is played using a Wintel Pentium PC. Of course the instrument can also play standard MIDI files, such as J.S. Bachs integral 'Goldberg' variations.
Most certainly, we are not the first to have automated the vibraphone. We recall very well the extensive work done in this field by our friends - at that time in Baltimore - Carney and Alec Bernstein. But sure enough, many more instrument builders have untertaken this task before. Of course we are not forgetting the many pneumatic implementations found in the large dance organs (orchestrions) from the interbellum, although these were pneumatic and pretty primitive. So, when we started our own attempt to realize an automated vibraphone, we could build further on these experiences and take off from there.
Our own design had to become a computer controlled acoustic vibraphone with touch control and individual dampers for each bar. The starting point for the practical construction was an small-model Yamaha vibraphone (type YV-600B, serial number 1977) of which we only kept the tuned aluminium staves and the resonators. The original global damping mechanism (activated by the pedal) was thrown out altogether. A new electric circuit was designed for the vibrato mechanism, since the original one was too noisy and could not be easily computer controlled. The beaters make use of Lukas Ledex solenoids, mounted under the extremities of the sound bars. The dampers were made with the same type of solenoids, but here we mounted rubber or felt pads on the anchors as dampers. No springs were used. The anchors fall back on a heavy felt covered steel bar by gravity alone. The design started off with an analysis of pulse timing requirements for the automated vibraphone. The attack pulse tv1.tv2... (for power supply voltage of 44V -see further) should range between 3ms and 15ms. If we want good dynamic control, it is enough to control precisely the pulse width of the attack solenoids with the beaters. The pulse duration for the dampers could be constant and, if so, equal to the minimum pulsewidth required to damp the bar (ca. 50ms). At rest, the damper can be released, so no power is spoiled. The maximum repetition speed depends on the dynamic used and is limited anyhow by the time required for the beater to fall back plus the time for the damper and the time for this damper to fall back. Of course, when playing very fast repeated notes one could decide not to use the dampers. But even then, the repetition rate will be determined by the time it takes for the beater to fall back. If we mount the achors with springs, the fallback time can be decreased, but only at the detriment of dynamic range: the height of the (compressed) spring should be subtracted from the original movement traject. Also springs unavoidably introduce their own resonant frequency, interfering with some repetition rates.
This design offers many more musical perspectives than either what musician playing vibes could have to offer. First, it is truly polyphonic with complete autonomy for the individual beaters. So no longer a limitations to 2, 4 or if conservatory acrobatics are used, 6 notes or sticks. Second, as we provided individual dampers for each bar, the musical possibilities in terms of expressive refinement are greatly enhanced. Third, since we finally decided to also implement velocity for the dampers, we can control the damping up to the smallest detail. This way even the most 'avant-garde' playing techniques can be realized on this automat. What we have not implemented is changes of sticks, as musicians are often required to do in pieces. This would have required at least yet another row of solenoids with softer beaters. There is barely enough space under the bars to allow for such an untertaking. Of course we could place them above the bars, but then one potential element of magic in the instrument would disappear: the possibility of manualy playing the instrument at the same time as its automat plays. Nevertheless it requires the user only to exchange 37 beatercaps if it is really required to sound this vibraphone with a softer attack.
A new element in the design of this instrument is the implementation of a damper-hold mode, whereby the felt covered dampers can be pushed against the staves with a continuously variable force. Thus the staves can also be played whilst damped to a variable degree. It was easy to implement this since 8254 type timer chips can be programmed to operate either as programmable one-shots or as square wave generators. In the latter case, since their outputs drive the solenoids via mosfets, we take profit of the fact that the coils impedance rises with the frequency of the applied voltage. Thus the current through the solenoids can be controlled by programming the periodic frequency of the timer chips. At some operating frequencies in the audio band however, this operational mode can lead to audible noise stemming from the solenoid anchors.
As usual in our instrument designs, we constructed TIG welded steel frames for the entire magnet and electromechanics assembly. Bolts on the sides of the instrument in combination with the bolts holding the fallback bars under the solenoids allow for fine adjustment of the traject of movement for the beater and the dampers. This affects the dynamic range. The instrument was mounted on large and very sturdy wheels of the same type as used in most of our other robots.
The note range of the instrument is 37 notes (C-c"), 60 to 96 expressed in MIDI notes.
This instrument is a computer controlled acoustical angklung. It is mounted on a heavy duty trolley and can be taken on the road for street performances. In this case it is powered by a set of 3 12V lead batteries and control / programming takes place using either a subnotebook PC or a specific dedicated and preprogrammed microcontroller.
There are 20 anklung-notes in the intrument, each note always sounding in 3 octaves, as usual on the original Indonesian instruments, made of bamboo. Our anklung however does not use bamboo but brass tubing and was rebuilt from an old German instrument designed to be used in the circus. The original instrument was made for a musical clown and even had small electric lights fitted. This use explains why the tuning of the instrument conforms to A=440Hz and is tuned in equal temperament. The ambitus is C#-a (49 - 69). The angklungs are actioned by strong bidirectional solenoids. These are rated nominally 24V / 1A delivering a force of 24 Newton. In order to get a higher range of striking velocities, we operate these solenoids at twice the rated voltage, limiting the duty cycle to 25%.
This instrument is a computer controlled assembly of seven single skin drums of increasing sizes (from 70cm to 7 cm). Each drum has a set of different beaters. Since the smallest drums do not have enough place to accomodate a large number of beaters, this number decreases with the size of the drums. The beaters are arranged such that the rightmost beater always hits the center of the drumskin. The leftmost beater is positioned such as to obtain a rimshot. Other beaters occupy intermediate positions. The drums are mounted in an assembly with an angle of 36 degrees, on a sturdy three-wheel base.
The complete structure is made of steel and was almost entirelly welded using TIG technology. The instrument can be played by standard MIDI commands, using our GMT software but is also capable of listening to pure algorithmic commands. The MIDI command converter was written by Kristof Lauwers. The MIDI mapping is as follows:
on Godfried-Willem Raes' automatons can be found on the extensive Logos website (www.logosfoundation.org), and more specifically on the special <Automatons> page: http://www.logosfoundation.org/instrum_gwr/automatons.html
Theory into practice: the <M&M> Ensemble
Human performers (flutist and live electronics expert Karin De Fleyt, tuba player Leonaar De Graeve, violinists Moniek Darge and Stefaan Smagghe, programmer and guitarist Kristof Lauwers, double bass-player Xavier Verhelst and of course Godfried-Willem Raes himself) research the possibilities of interaction between themselves (the first M: Man) and the imaginative installations (the second M: Machine).
Own compositions form the core of their repertory, but we hope to add to this interpretations of visionary ideas from the past, such as the legendary futuristic noise machines. Also planned is the performance of Godfried Willem Raes' anti-opera TechnoFaustus.
Meanwhile, these are our most performed pieces:
Thomas Smetryns „for Brent Wetters II“ for Klung
Kristof Lauwers „ß-troms“ for Troms
Kristof Lauwers "Generic Sonata" for complete automat orchestra
Kristof Lauwers & Moniek Darge "MachineWall 1-8", for robot orchestra and musicians
Kristof Lauwers & Godfried-Willem Raes „Springers“ for Springers
Kris De Baerdemacker „Plpvhp“ for player piano, Piperola and Vox Humanola
Stefaan Smagghe "Communications" for violin and robot orchestra