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INTERACTIVE INFRASONIC ENVIRONMENT:
A New Type of Sound Installation for Controlling Infrasound
Reinhard Gupfinger, Hideaki Ogawa, Christa Sommerer, Laurent Mignonneau
Graduate School of Interface Culture
University of Art and Design Linz
Linz, Austria
{ reinhard.gupfinger, hideaki.ogawa, christa.sommerer, laurent.mignonneau } @ufg.ac.at
ABSTRACT
This paper proposes a new type of interactive sound
instrument for use with audiences in sound installations
and musical performances. The Interactive Infrasonic
Environment allows users to perceive and experiment with
the vibration and acoustic energy produced by infrasound.
This article begins with a brief overview of infrasound and
examines its generation, human perception, areas of
application and some odd myths. Infrasound is sound
with a frequency lower than 20 hertz (20 cycles per
second) – outside the normal limits of human hearing.
Nevertheless the human body can perceive such low
frequencies via cross-modal senses.
This paper describes three key aspects of infrasonic sound
technologies: the artificial generation of infrasound, the
human perception of infrasound, and the interactive
environment for sound installations and musical
performances.
Additionally we illustrate these ideas with related works
from the field of sound art and interactive art.
Keywords
sound installation, interactive environment, infrasound,
video tracking system.
1. INTRODUCTION
Our idea for building an interactive system that uses
infrasound came from the myth of “Demutspfeife” in
which a single tone from an organ brings humility to its
listeners. The legend says that these big organ pipes are
often used in churches to subdue people. While
researching the field of infrasound further myths about the
affects of infrasound on humans were found. We focused
on the possibility for bringing infrasound to audiences in
sound installations and musical performances wherein the
users could experiment with infrasound on their own
bodies. With this project we attempt to increase acoustic
awareness by sensitizing people to very low sound
frequencies. This sense is still underdeveloped in our
culture.
A main problem was just how to generate infrasound.
There are only a few possibilities and most of them would
be unsuitable for an audience in a sound installation. Due
to the fact that sound installations tend to be difficult to
perceive and understand for the audience we wanted to
create a simple interactive environment that offers a great
deal of creative freedom and options for the users.
We could not find many artistic projects relating to the
field of infrasound but there have been a number of
studies from several areas of study such as medicine,
weaponry and noise reduction. There are too many facets
to this research and far too much speculation on
infrasound to fit within the scope of this paper.
2. INFRASOUND
Infrasound is sound that is lower than 20 cycles per
second. This is sound that is just below the lower limit of
the human sense of hearing.
Sound range Frequency Wave length
Infrasound 1 Hz < ƒ < 20 Hz 1 Hz = 1125 ft = 342,9 m
Hearable sound 20 Hz < ƒ < 16 kHz 20 Hz = 56 ft = 17 m
SMC 2009, July 23-25, Porto, Portugal
Copyrights remain with the authors
2.1. The Generation of Infrasound
Table 1. Sources of infrasound
2.2. The Human Perception of Infrasound
Hearing does not abruptly stop below 20 Hz. As careful
measurements have shown, with high enough sound
pressure the ear can register infrasound down to about 1
Hz. [1] Infrasound perceived as a mixture of auditory and
tactile sensation at a high threshold level.
Sense
Perception
- Ear
- Skin
- Viscera
- Sinuses, nares, chest, bowel
- Eye
- Feeling of pressure
- Pulsation and vibration
- Resonance vibration
- Barometric variation
- Vibration
Table 2. The human perception with cross-modal senses
Infrasound especially affects the cavities of the human
body though its affect on air pressure. Different pitches and
intensities of infrasound can be perceived as changes in
pressure and vibration. The effects of very low frequency
noises such as infrasound on human beings have been
documented in many articles; these include: temporary
hearing threshold shifts, changes in blood pressure, changes
in heart rate, changes in respiratory rate, balance
disturbances, cognition disturbances. [2]
During medical research at the Hellersen Hospital in
Lüdenscheid (Germany) the psychosomatic effects of
infrasound were tested on people with chronic pain. Six
inpatients suffering with chronic pain were exposed to
infrasound at 9 Hz for 20 min per day. After one week
they concluded that infrasound activates the autonomic
nervous system and has positive effects on stress and also
has a palliative effect on pain. [3] If the sound pressure of
infrasound is higher than 120 dB, negative effects of
infrasound appear: headache, breathing problems, changes
in heart rate and general stress. Constant pressure (more
than 10 minutes) with infrasound at more than 170 dB
causes the death of the test animals. [4] Additionally there
is an additional impressive effect, which is produced by
infrasound. A NASA technical report mentions a resonant
frequency for the eyes of 18 Hz (NASA Technical Report
19770013810). In this case the eyeball would begin
vibrating which would cause a notable “smearing” of
vision. [5] Vic Tany outlines the idea that a standing wave
of 19Hz could, under certain conditions, generate sensory
phenomena suggestive of a ghost in his paper “The Ghost
in the Machine” from 1998.
2.3. The Areas of Application for Infrasound
Infrasound is currently being utilized in various fields. A
relatively new discipline is the medical use of infrasound
therapy. It is useful in treating chronic pain and
arteriosclerosis wherein vibrating medical devices are
attached to the body.
Interest in atmospheric infrasound peaked during the Cold
War, as it is one of several ways to detect, locate, and
classify nuclear explosions at very great distances. At
present the Comprehensive Test Ban Treaty requires a
more sophisticated global sensor network to monitor
compliance. [6]
A global network of infrasonic detectors has been installed
to observe the atmosphere. The intention is the early
detection of meteorites, tornados, earthquakes and volcanic
eruptions. In the 1970s, the National Oceanic and
Atmospheric Administration began a study of atmospheric
infrasound to determine whether it could be used to
improve warning capabilities for severe weather events
such as tornadoes. [7] They found that many
thunderstorms radiated infrasound, which could be detected
by observatories more than thousand miles away.
2.4. Infrasound Myths
The most bizarre myth about infrasound is the brown
note. As the name implies, it is assumed that this is an
infrasound frequency, which causes humans to lose
control of their bowels. There is no scientific evidence
that such an infrasound note exists.
Another legend is about infrasound weapons. Some
infrasound review articles mention the fact that several
countries have investigated this possibility. Such an
infrasound weapon would be a huge installation that could
generate high-pressure low frequencies, which would cause
anxiety, internal injuries and death to humans.
Finally there is the myth of “Demutspfeife” that was
mentioned earlier. It is a single organ pipe and part of a
church organ, which brings humility to its listeners. Our
Interactive Infrasonic Environment project strongly
references this idea, but we do not intend to bring any
Natural sources:
Artificial sources:
- Wind and atmospheric
turbulence
- Earthquakes and
volcanic eruption
- Waterfalls and breaking
waves
- Animals (e.g. whales,
elephants, rhinoceros,
giraffes, okapi and alligators)
- Air conditioning systems
- Wind energy turbines
- Gas turbine power stations
- Industrial facilities (e.g.
compressors, compactors)
- Buildings
(e.g. skyscrapers, tunnels,
bridges)
- Vehicles(cars and trucks,
trains, ships, planes)
- Explosions
-Speaker systems
- Organ pipe
negative effects of infrasound. We propose a strictly
positive application of infrasound and low sound
frequencies.
3. INTERACTIVE INFRASONIC ENVIRONMENT
As there are so many fascinating aspects and also a few
strange myths concerning infrasound, we started to
develop an infrasonic installation in early 2007.
The goal of the project was to make infrasound
approachable for everyone. We attempted to build an
installation where the audience can experiment with the
perception of infrasound regardless whether it creates a
positive or negative effect in their bodies. For this reason
we soon realized that an important part of the installation
would be a multiple-user interface through which all users
can interact simultaneously and in real time.
The Interactive Infrasonic Environment is the first
interactive instrument that allows users to generate
infrasound while moving around the space. It is an
installation that overlaps auditory and tactile stimuli to
increase the level of acoustic awareness.
3.1. The Organ Pipe
The installation hardware is based on a 19 ft wooden
organ pipe placed in the center of the environment. The
pitch of the pipe can be tuned with an adjuster at the end
of the organ pipe. The wavelength of the pipe is modified
to the characters and sizes of the room in which the
installation is located. Adjustments are needed to get
satisfying resonates from the specific architecture of the
room. The organ pipe can generate sound frequencies
down to 15 Hz, going beyond the limits of human
hearing.
Figure 1. Dimensions and tone pitch of the organ pipe
3.2. Sound Generation
The sound of the pipe is produced via the vibration of air
in the same way as a flute. The airflow is driven over an
open aperture and against a sharp lip called a labium. The
airflow begins fluttering and creates high and low pressure
waves within the pipe's air column. The low sound wave
generated has a frequency between 15 Hz and 17 Hz. As
described earlier the tuning of the organ pipe depends on
the size of the room. The vibration energies of infrasound
are transmitted to the human body and the architectural
space enhances the natural resonance of both. The source
of a sound in an interactive computer based instrument is
not some abstract or concrete concept, or even the
algorithm(s) that have been written; it is the gesture of the
performer, the excitation moment - it is fundamentally
about that nature of excitation. [8]
3.3. Video Tracking System
Interaction with an instrument that uses video tracking is
a particular case in point, for the nature of engagement is
abstract, and as such is based not so much on the physical
relationship of the self to the physical space that houses
the instrument or interactive installation. [9] The project
uses a video camera situated high on a wall, which
continuously observes the surroundings of the organ pipe,
tracking the position and movement of the users. The
software is programmed in Max/MSP and uses the
Cyclops object to receive and analyze video input. The
program rasterizes the video input and analyses the
grayscales of predetermined zones. The users interact by
moving around and changing their positions. These
actions directly control the wind machine, which is
fluently controlling the airflow and thus the volume and
pitch of the organ pipe.
Figure 2. Schematic view of the Interactive Infrasonic
Environment
3.4. Experiments with Test Subjects
During the first testing phase we explored the sensations in
the Interactive Infrasonic Environment with the help of ten
participants. We performed separate individual experiments
by using an exposure chamber. A single experiment
consisted of three 5 min exposure periods and after each
period a 15 min post exposure period, including a short
interview of the test subject. The test was performed with a
continuous tone at a frequency of 15 Hz and three different
sound intensities: low, middle and high. The goal of these
experiments was to establish the connection between the
Interactive Infrasonic Environment and psychoacoustic
human perception. The experiments showed that the low
sound frequencies produced feelings of pressure, pulsation
and vibration on cross-modal senses for all test persons. It
was surprising that the threshold where the test persons
started to feel uncomfortable varied from person to person.
For two subjects the feeling of discomfort started at the
second level of intensity and for five subjects it started at
the highest level. For the other subjects (3) there were no
uncomfortable feelings experienced during the entire test
period. Physical contact with the vibrating organ pipe was
enjoyable for all test participants.
3.5. Present and Future Work
To date the Interactive Infrasonic Environment installation
has been shown at several exhibitions. The feedback from
the audience and the curators confirmed our intention to
continue with and further expand this infrasonic project.
Figure 3. Interactive Infrasonic Environment, Sound
Characters exhibition, Innsbruck, 2009
We are currently working on and researching a musical
performance using the Interactive Infrasonic Environment.
We use infrasound to conduct a choir and likewise the
members of the choir can control the infrasound through
the installation. The first live performance was staged in
May 2009 in Linz (Austria), the European Cultural
Capital at the time. The members of a women’s ensemble
improvised to the accompaniment of the Interactive
Infrasonic Environment. With certain sequences of
movements, members of the choir could steer the tones
produced by the organ pipe. The tones generated by the
organ pipe in turn provided the impetus for tonal
variations in the choir’s singing.
Figure 4. Improvisation Concert for Choir and Organ
Pipe, Linz, 2009
4. RELATED WORKS
There have been a several studies and projects concerning
infrasound in the field of media art. We want to highlight
a few of the projects that inspired our vision of an
interactive infrasonic installation. The last example refers
to our video tracking system, which is a basis to a certain
extent on the milestone of the interactive sound
installation.
4.1. IIT
The Infrasonic Transmission Tube was designed and
constructed by Laton, a research lab and record label based
in Vienna. The prototype sound system was able to
generate infrasound frequencies from 1 Hz to 20 Hz. They
used the Infrasonic Transmission Tube for their realization
of their self-titled "Infrasonic Music". The project was
shown at the Ars Electronica Festival in 1996.
4.2. Live Room
Mark Bain developed the Live Room in 1998. It was a
project that used small acoustic-intensifying machines,
which were attached directly to the structure of a room.
The installation incorporated the architecture by running
impulsive energy throughout, creating sound and vibration
in direct relation to the building and the dimensions of the
space. With this work, I was interested in
TRANSDUCING ARCHITECTURE, driving the space
with external influences of a vibro-kinetic nature. [10]
Bain was able to effectively tune a space by delivering the
resonant frequency to its different parts. The Live Room
also generated infrasonic sound, which brought strangeness
to this project related to the production and injection of
these unique low frequencies.
4.3. Very Nervous System
In 1982 the Canadian Artist David Rokeby started to
develop his Very Nervous System, an interactive sound
environment with a real time motion tracking system.
Video cameras observed the users action and a computer
analyzed the data and responds acoustically to the input. It
was the intention to design a space in which the
movements of one’s body create sound. David Rokeby
was interested in creating a complex relationship between
the user’s body and the system. “Because the computer is
purely logical, the language of interaction should strive to
be intuitive. Because the computer removes you from
your body, the body should be strongly engaged. Because
the computer's activity takes place on the tiny playing
fields of integrated circuits, the encounter with the
computer should take place in human-scaled physical
space. Because the computer is objective and
disinterested, the experience should be intimate.” [11] In
the early days of interactive art, the interaction with the
Very Nervous System was very novel because the interface
was invisible. The system was used in performances,
exhibitions and additionally in music therapy
applications.
5. CONCLUSION
In summary, this paper provides a brief overview of
infrasound, its generation, perception, areas of application
and myths. We noted that there is a need to sensitize
people to allow them to better register infrasound and that
our project intends to increase acoustic awareness; this is
still an underdeveloped sense in our culture.
This paper presented a new type of interactive sound
instrument that allows users to experiment with the
vibration and acoustic energies produced by infrasound.
The challenge for this project was to construct a sound
generator, which produces perceptible infrasound. As a
final remark we would like to say that there is still much
work to do in order to fully implement all of our ideas,
especially those involving live musical performances.
6. REFERENCES
[1] Altmann, J. ''Acoustic Weapons—A Prospective
Assessment: Sources, Propagation, and Effects of
Strong Sound” Cornell University Peace Studies
Program, Dortmund, 2008.
[2] Takahashi Y. “An Infrasound Experiment for
Industrial Hygiene” Industrial Health 32, p. 480,
1997
[3] Deutschmann-Hütt, H. “Psychosomatische Wirkung
von Infraschall am Beispiel chronischen Schmerzes”
Sportkrankenhaus Hellersen, Lüdenscheid 2005.
[4] El-Nounou, M. “Messung und Bewertung von
niederfrequenten Luftdruckschwankungen und
Infraschall in Personenkraftwagen bei
unterschiedlichen Fahrbedingungen” Ludwig-
Maximilans-Universität, München, 2006.
[5] Tany, V. “The Ghost in the Machine” Journal of the
Society for Psychical Research Vol. 62, 1998
[6] National Research Council, “Research Required to
Support Comprehensive Nuclear Test Ban Treaty
Monitoring” National Academy Press, Washington,
DC 1997.
[7] Georges, T. M. “Instruments and Techniques for
Thunderstorm Observation and Analysis”, E.
Kessler, ed., U. Oklahoma P., Norman, Okla. 1988.
[8] Traube, C., Depalle, P., Wanderley, M. “Indirect
Acquisition of Instrument Gesture Based on Signal,
Physical and Perceptual Information”, NIME 2003
[9] Paine, G. “Gesture and Musical Interaction:
Interactive Engagement Through Dynamic
Morphologie” NIME 2004
[10] Bain, M. “The Live Room: Transducing Resonant
Architectures” Cambridge University Press, New
York. 2003
[11] Rokeby,D.
http://homepage.mac.com/davidrokeby/vns.html
