VIRTUAL EXPERIENCES (p.1)
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This
obscure title announces our intention to consider
and analyse what goes into the creation of a "virtual
experience", or rather all the "real" and tangible
technology available to the composer nowadays. Such
technology is used to express - and therefore turn
into vibrations captured by the ear and subsequently
perceived by the brain as sound - the "virtual" compositional
ideas which are the product of the creator's imagination
and fantasy in order to make these experiences available
to everyone. |
The term 'hardware' refers to all the equipment used by
the musician in the various stages of the compositional
process leading to the production of a "Cybertrack".
The history of electronic music is to be considered part
of the "old ideas", created through the use of electronic
instruments which evolved rapidly due to the incredible
progress made in the field of electronics and computer science;
"old ideas" because most of the audio synthesis, processing
and recording systems were already theorised, analysed and
defined many years ago but they have had to wait for the
necessary technology to be transformed into "virtual" and
"real" concepts.
We will now just take a brief look at the milestones in
this evolution of the use of electronic means to produce
synthesised sounds and music and leave to a later date a
more in depth discussion of the technology that has made
possible the creation of the Cybertracks project.
As already mentioned, the most important developments in
sound synthesis came about following important progress
in the fields of electronics and computer science. It is
true however, that very often many years passed, even decades,
between the time a technique was theorised and studied until
when it became practically available and therefore applied.
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of the first serious musical instruments to produce
sound using purely electronic means was the Teleharmonium,
designed and built by Thaddius Cahill as far back
as 1903. The "sound" was produced by special, enormous
electric generators each of which generated AC current
(the current that runs through the domestic system
oscillates at 50 Hertz, almost the equivalent of the
note G1), with frequencies corresponding to the same
note for the various octaves of the organ keyboard.
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The basic timbre, fundamentally a perfect sine wave, was
varied by adding together the outputs of the different generators
through heavy transformers to create a sort of primordial
additive synthesis. The intensity was regulated by moving
the nucleus of enormous coils. As the signal was continuously
generated the keys of the keyboard acted as simple switches,
allowing the signal to pass but in turn generating a large
amount of noise and clicks.
The whole box of tricks was somewhere around 200 tons!
The basic concept of electrical generators was later taken
up and perfected by organ makers Hammond, famous for their
distinctive sound and that characteristic "click".
Some years later, when sound was added to films after 1930,
experiments were made drawing the waveform directly onto
film. Theoretically this technique should have been extremely
powerful as it meant that any sound at all could be "drawn"
but the problem was knowing exactly what to draw in order
to obtain the sound required!
This concept of waveform drawing is now very familiar to
us and modern samplers and computers with their various
programs and functions take over the laborious process of
calculation, synthesis and drawing the actual waveform for
us.
Without doubt the most significant development in the use
of electronic means for producing, and above all for recording
music, was the advent of the tape recorder. Originally produced
in Germany during the second world war, it made use of a
metal wire to record on; later the technique was refined
using a paper tape covered in iron oxide, and then eventually
in later years plastic tape covered in magnetised iron particles.
Sound "captured" through such a system became a physical
entity and could therefore be cut, rearranged, inverted,
modelled and easily re-recorded. By merit of this, a new
compositional form was born by the name of "Concrete Music"
in which mainly natural or "concrete" sounds were used for
transforming into sounds previously unheard by means of
varying the tape speed, cutting and splicing the different
sound segments which had been inverted, overdubbed or manipulated
in various other ways.
This idea gave rise to the first echo simulation using the
tape recording head of one machine combined with successive
playback heads spaced apart in such a way as to simulate
a delay between one sound repetition and another.
Over the years different specific apparatus has been used
for sound synthesis (nothing to do with natural sound therefore)
such as the Theremin (1920), the Novachord (1938), the Melochord
(1949), up to the early 1950's when the first real electronic
sound synthesiser arrived, the RCA Mark II Electronic Music
Synthesiser.
This was a very large valve-based machine able to generate
two sounds simultaneously for which all the main parameters
could be controlled by a method of programming on a roll
of perforated paper. The same system of perforations on
paper discs stored the programmed sequence of notes or sound
events which were then reproduced automatically, perfectly
synchronised with the timbral variations perforated on the
other roller.
Extensive use of this machine highlighted the need for substantial
programming preparation in order to adequately vary all
the sound parameters which the technology had made available.
This therefore led in the 1960s to the adoption, for musical
purposes, of large computers which were built in the research
centres and universities using a simple piece of equipment
(DAC) which converted the numbers issuing from the electronic
"brain" into signals that could be used in amplification
and loudspeaker systems.
| This
system known as "Direct Computer Synthesis" or also
synthesis in deferred time, is extremely flexible
since each sound source, whether natural, synthetic
or - and here's the novelty - imaginary or virtual,
can be described by means of a mathematical model
which a suitable program can calculate to produce
the numbers which describe the sound. The more accurate
the mathematical model, the more accurately the natural
sound will be reproduced. |
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There is no limit to the number of simultaneous sounds that
can be calculated; the only drawback with this system is
the time it takes for the computer to process all the model
parameters. The more complex the sound, the more time it
takes to calculate and so the resulting sound cannot be
immediately verified or used in real time performance. In
the same way, to obtain satisfactory results considerable
knowledge of the relationship between the mathematical model,
the sound parameters and the final listener's perception
is necessary. Many of these problems have been partially
overcome due to the enormous power and speed of modern computers.
It was to face this very time problem and to combat the
costly and not very useful direct computer synthesis that
in the second half of the 1960s, thanks to the invention
of the transistor, a different modular form of synthesis
was developed. In this system each single module plays a
particular role in the process of signal generation, modification
and processing by the musician/composer acting directly
on the various sound parameters. Consequently, immediate
verification of results can be achieved therefore in real
time. These parameters are modified using knobs which vary
a control voltage necessary to obtain the corresponding
variation in the particular parameter, and hence the name
"Voltage-Controlled Synthesiser". The only trouble with
the first synthesisers of this type and until recent years
was that they could only generate one note at a time (monophonic)
because of the intrinsic limitations of the technology applied
which only later digital techniques could overcome.
The pioneer of this system was Robert Moog, whose machines
Walter Carlos used in 1969 to create "Switched On Bach",
an excellent reworking of some Bach compositions which made
electronic music more palatable compared to the previous
concrete music. Later developments are more modern history
where such protagonists as microprocessors, computers, synthesisers,
digital signal processors, digital recording etc. have become
fashionable bywords on everyone's lips and it is precisely
for this reason that some clarifications need be offered
as to what all this really means.
LINKS
L'inventore del Teleharmonium http://www.obsolete.com/120_years/machines/telharmonium
Il
museo dei sintetizzatori
http://www.synthmuseum.com/
La pagina dedicata al primo synt
http://www.synthmuseum.com/magazine/0102jw.html
Esperimenti per suonare online
http://www.gmeb.fr/InstrumentsVirtuels/cahill/virtual.html
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